This roasted banana ice cream has a delicious flavour reminiscent of roasted apple pie. Roasting the bananas reduces their water content and intensifies the sweet banana flavour. It will be split into three sections: SECTION 1 will cover the science of ice cream making and preparation tips, SECTION 2 the ingredients and a detailed recipe, and SECTION 3 a quick recipe. I strongly recommend starting with section 1.
SECTION 1: THE SCIENCE OF ICE CREAM MAKING AND PREPARATION TIPS
THIS RECIPE WAS UPDATED ON 13TH FEBRUARY 2016
1. Freezing the bowl and equipment
For this recipe, I use the Cuisinart ICE 30BC (click here for my review), which comes with a removable bowl that needs to be frozen overnight before it can be used. The following is a list of domestic ice cream machines with in-built compressors that I’ve tried and would recommend:
- Lello Musso Pola 5030 (click here for my review),
- Lello 4080 Musso Lussino (click here for my review)
- Cuisinart ICE-100 (click here for my review)
- Breville BCI600XL (click here for my review),
To view the top selling ice cream makers on amazon, please click here
TIP#1 – Cling film
For the Cuisinart ICE-30, the day before you start making your ice cream, take the bowl and cover the top with cling film; use an elastic band to help keep it in place. The cling film will help prevent water vapour in your freezer, as well as any ice that may fall in, from freezing to the inside of the bowl. Any water that freezes at the bowl wall will likely be incorporated into the mix during the churning process, with possible implications for texture if a sufficient amount is incorporated.
It’s also important to freeze enough water in some ice trays to make an ice bath. We’ll be using an ice bath to quickly cool the ice cream mix once it’s been heated, minimising the time the mix spends in the ‘danger zone’, between 5 (41) and 65°C (149°F), where bacteria likes to multiply.
TIP#2 – Freezing the container
Take a 1 litre plastic container and the freezer bowl and put them in your freezer overnight. Freezing the plastic container will remove any stored heat. Heat stored in the container causes the ice cream that contacts the side and bottom to melt, resulting in an increase in ice crystal size.
1.1. Ice crystals in ice cream
Ice crystal size is a critical factor in the development of smooth and creamy ice cream (Donhowe et al. 1991). Smooth and creamy ice cream requires the majority of ice crystals to be small, around 10 to 20 µm in size. If many crystals are larger than this, the ice cream will be perceived as being coarse or icy (Drewett & Hartel 2007; Goff & Hartel 2013).
Ice crystal size is determined by the mix composition and by the freezing process, of which there are two stages: 1. the dynamic freezing stage, where the ice cream mix is frozen in an ice cream machine while being agitated to incorporate air, and 2. the static freezing stage, where the partially frozen ice cream is hardened without agitation in a freezer. Ice crystals form only during the dynamic freezing stage and grow during the static freezing stage.
In this recipe, we will be looking at what we can do to promote the development of small ice crystals during the dynamic freezing stage and then preserve these small crystals during the static freezing stage.
2. Setting the freezer temperature
Your freezer’s temperature has a significant effect on residence time and on ice crystal growth.
2.1. Residence time
If you’re using the Cuisinart ICE 30BC, or any other machine that requires you to freeze the bowl before it can be used, your freezer’s temperature will have a considerable effect on residence time. Residence time is the length of time the ice cream mix spends in your ice cream machine during the dynamic freezing stage and has a significant effect on ice crystal size (Russell et al. 1999; Goff & Hartel 2013; Drewett & Hartel 2007; Cook and Hartel 2010). Russell et al. (1999) found that ice creams made with shorter residence times had smaller ice crystals.
Your freezer’s temperature determines the temperature of the freezer bowl when you leave it to freeze overnight. Lower freezer bowl temperatures can lower the bulk temperature of the ice cream faster, reducing residence time and improving the ice crystal size distribution (Russell et al. 1999; Drewett & Hartel 2007).
TIP#3 – Lower your freezer’s temperature
Set your freezer’s temperature as low as it will go, ideally between -23 to -29°C(-9.4 to -20.2°F), to get your freezer bowl as cold as possible. The colder you can get your freezer, the colder it will get the freezer bowl and the shorter the residence time is likely to be. The shorter the residence time, the smaller the ice crystals and the smoother the texture is likely to be.
I’ve found that my freezer’s temperature has a noticeable effect on residence time when I use my Cuisinart ICE 30BC. When I set my freezer to ‘super freeze’, which gets the temperature down to about -27°C (-16.6°F), it takes about 18 minutes to churn an 800g batch of ice cream. When I set it to -18°C (-0.4°F), it takes about 30 minutes to churn the same amount.
2.2. Ice crystal growth
No new ice crystals are formed during the static freezing stage but the existing small crystals grow in size until the temperature decreases to -18°C (-0.4°F), or ideally -25 to -30°C (-13 to -22°F), to halt this growth. If the ice crystals grow too large during the static freezing stage, a corse or icy texture will develop (Arbuckle 1986).
Quick hardening during the static freezing stage limits ice crystal growth (Goff & Hartel 2013). Similarly, Donhowe (1993) showed that faster cooling of ice cream during hardening resulted in smaller mean ice crystal size.
TIP#4 – Promote quick hardening
To promote quick hardening during the static freezing stage, make sure your freezer is as cold as it will go, ideally -25 to -30°C (-13 to -22°F). Place your ice cream at the back of your freezer where it’s coldest. Try and clear some space in your freezer when chilling your ice cream. Putting ice cream in a densely packed freezer will reduce heat transfer, resulting in an increase in freezing time.
3. Setting your fridge temperature
It’s also important that you set your fridge to between 0 and 2°C (32 and 35.6°F) to increase the rate of crystallisation of the fat globules when you age your mix overnight. Crystallisation of fat during the ageing process helps maintain the shape of ice cream when it is served and also helps minimise the rate at which the ice cream melts (Goff & Hartel 2013). If you don’t allow the fat globules sufficient time to crystallise, it is likely that your ice cream will suffer from relatively fast meltdown and less retention of shape.
4. The size of your pan
The size of the pan you use will affect the rate of evaporation and heating time. I use a large pan with a 23cm diameter to achieve a 15% reduction after 25 minutes heating at 72°C (162°F). If your pan is smaller than 23cm, you will likely need to continue heating your mix for a further 5 minutes or so to reach the desired 15% reduction. Let’s have a look at why it’s important that you heat your mix for the full 25 minutes at 72°C (162°F) and achieve at least a 15% reduction. .
5. The importance of heating time and temperature
There are three principal reasons why we will be heating our mix to 72°C (162°F) and holding it there for at least 25 minutes: 1. to pasteurise the mix, 2. to improve foaming and emulsification, and 3. to improve body and texture.
5.1. Pasteurisation
If you’re running a business and making ice cream to sell, you need to ensure that you are in compliance with food safety legislation. Here in the U.K, the Dairy Products (Hygiene) Regulations 1995, Schedule 6, part v 1 (a) states:
1. Pasteurised ice-cream shall be obtained by the mixture being heated—
to a temperature of not less than 65.6°C (150.1°F) and retained at that temperature for not less than 30 minutes;
to a temperature of not less than 71.1°C (160°F) and retained at that temperature for not less than 10 minutes; or
to a temperature of not less than 79.4°C (174.9°F) and retained at that temperature for not less than 15 seconds.
Ice cream needs to be pasteurised in order to destroy all pathogens and the enzyme phosphatase that may be harmful to health. This is just as important for those of us making ice cream to sell as it is for the home cook.
5.2. To improve foaming and emulsification
The second reason we’ll be heating our mix to 72°C and holding it there for 25 minutes is to improve whey protein foaming and emulsification. Foam formation and its stability is important for texture and for the retention of air that is incorporated into the ice cream during the dynamic freezing stage. Heating milk so that the whey proteins undergo partial protein unfolding yields a more voluminous and more stable foam and improves the emulsifying characteristics of milk protein (Philips et al., 1990). At high temperatures, however, foaming and emulsifying characteristics may be impaired due to protein aggregation (Phillips et al., 1990).
At what temperatures, then, do the whey proteins found in milk start to undergo beneficial partial protein unfolding and at what temperatures do they start to aggregate? Sava et al. (2005) held that thermal denaturation of whey protein involves 2 steps: an unfolding step at 70 to 75°C (158 to 167°F), and an aggregation step at 78 to 82.5°C (172.4 to 180.5°F), that mostly follows unfolding.
TIP#5 – 72°C (162°F) for 25 minutes
I’ve found that when I hold my mix at temperatures above 72°C (162°F) for a prolonged period of time, the unpleasant ‘eggy’ hydrogen sulphide taste begins to form and becomes noticeable on eating. I would therefore recommend heating your ice cream mix to 72°C (162°F) and holding it at this temperature for 25 minutes as this significantly improves ice cream body and texture. I’ve run several tests where I have kept the temperature constant at 72°C (162°F), as well as the composition, but have varied the heating times. I’ve found that a mix heated for 25 minutes produces smoother and creamier ice cream than compared to mix heated for 5, 10, and 15 minutes at the same temperature.
5.2.1. Surface hydrophobicity
Surface hydrophobicity is also important in determining emulsifying activity (Monahan et al., 1993). Damodaran (1996) held that denatured proteins have better foaming properties, attributed to increased hydrophobicity, and greater interfacial contact. Sava et al (2005) found that surface hydrophobicity increased considerably at temperatures between 70 and 77.5°C (171.5°F) when whey protein was heated for 45 minutes, with greater increases noted after longer heating times.
Functionality of whey protein also depends on its solubility. Heating at a temperature between 70 (158) and 75°C (167°F) results in a minimal loss of solubility. Sava et al. (2005) noted a decrease in solubility of only 10 to 20% compared with the native protein after 45 minutes.
The literature points to an optimal heating temperature for whey protein at somewhere between 70 (158) and 75°C (167°F). In this temperature range, whey proteins undergo reversible unfolding, which improves foaming and emulsification. Holding whey protein at between 70 (158) and 75°C (167°F) for an extended period of time significantly increases surface hydrophobicity with only a minimal loss of solubility, which improves foaming.
5.3. To improve body and texture
The third reason we are going to heat our ice cream mix to 72°C (162°F) and hold it there for 25 minutes is that heating milk also improves body and texture because of the denaturation of proteins and the consequent increase in their water-holding capacity (Goff & Hartel 2013), which contributes to smooth and creamy texture by helping to minimise ice crystal growth.
6. Weigh your pan
Before you start preparing your mix, it’s important to first weigh your pan and record its weight. This is necessary so that you can check the level of reduction after 25 minutes heating.
The starting weight of our mix will be 1000g. After 25 minutes of heating and a 15% reduction, you should have a mix weight of 850g plus the weight of your pan. If your mix weighs more than 850g plus the weight of your pan, put it back on the heat and continue heating.
Here is how to check the level of reduction after heating for 25 minutes:
My 23cm diameter pan weighs 1606g.
1606g pan + 1000g starting mix = 2606g starting weight.
After 25 minutes of heating, my total weight (1606g pan + 850g 15% reduced mix) should be 2456g.
If my total weight after 25 minutes heating is greater than 2456g, I will continue heating until the weight falls to 2456g or less.
7. Why is skimmed milk powder added to ice cream?
The use of skimmed milk powder in commercial ice cream making is usually associated with economy-style ice cream as it is a cost effective way of reducing the more expensive cream whilst maintaining total solids. In homemade ice cream, however, I’ve found that it is essential for the promotion of smooth and creamy texture.
Skimmed milk powder’s primary role in homemade ice cream is to increase the non-fat milk solids (NMS), namely the whey protein. Flores & Goff (1999) demonstrated that milk proteins had a large impact on texture by limiting ice crystal size and enhancing their stability. I’ve not been able to achieve the same smooth and creamy texture in my homemade ice cream after 25 minutes of heating without the addition of skimmed milk powder.
SECTION 2: INGREDIENTS AND DETAILED RECIPE
Makes just under 1 quart (1 litre) of ice cream
PREP TIME:
About 15 minutes
HEATING TIME:
About 30 minutes for the mix
About 30 minutes for the roasted bananas
EQUIPMENT:
Food thermometer
Ice cream maker
A zip-lock bag
Ice trays
1 litre plastic container
Large bowl
Ingredients:
Cream
Full-fat, semi-skimmed, or skimmed Milk
Unrefined sugar
Skimmed milk powder
Egg yolks
For the roasted bananas:
450g very ripe bananas
20g brown sugar
1/4 tsp fine sea salt
1. The importance of butterfat
Milkfat contributes significantly to the rich, full, and creamy flavour and to the smooth texture of ice cream (Goff & Hartel 2013). It’s important that you check the fat content of the cream and the milk that you’ll be using in order to calculate your mix.
Above is the spreadsheet I use to calculate my mixes and I’ve included it for you guys to calculate the exact quantities of milk and cream that you will need. Simply enter the cream fat (usually found on the back of the cream carton and around 35% for you guys in the U.S) and milk fat percentages in the two yellow cells at the top of the spreadsheet. This will then give you the quantities of milk, cream, sugar, egg yolks, and skimmed milk powder needed (in grams) in the cells in blue.
You can use full-fat, semi-skimmed, or skimmed milk. Here in the U.K, our double cream and skimmed milk contain around 47.5% and less than 0.5% of fat respectively, which I have entered as the default values. I recommend using organic milk and cream and organic free-range eggs whenever possible. I use organic milk and cream and organic free range eggs for my business and find that I get a much richer flavour from organic milk and cream and a much deeper colour from free range egg yolks.
2. Preparing an ice bath
Before you start preparing your mix, take a large bowl and fill it with enough ice to make an ice bath. Have a large zip-lock freezer bag ready next to the bowl, along with some table salt. We will be using the zip lock bag and water bath to ensure that the mix is cooled as quickly as possible once it has been heated, minimising the time the mix spends in the ‘danger zone’, between 5 (41) and 65°C (149°F), where bacteria likes to multiply. The longer your mix spends in this ‘danger zone’, the more bacteria is likely to multiply, imparting an undesirable taste and smell.
3. Heating the mix
Weigh your pan and record its weight. We will use this weight to check whether we have achieved the desired 15% reduction after 25 minutes of heating.
Once you’ve prepared the ice bath and weighed your pan, add the sugar and skimmed milk powder followed by the egg yolks. Mix the yolks, sugar and skimmed milk powder to help prevent the yolks from curdling during heating.
Add the cream and milk and spend a good minute or so mixing all the ingredients before you switch on the heat.
Over a medium heat, heat the mixture until the temperature reaches 71°C (160°F), making sure that you are constantly stirring. You’ll risk burning the proteins and curdling the egg yolks if you do not constantly stir the mix.
Once the temperature reaches 71°C (160°F), turn the heat down to medium-low, move your pan slightly off the heat, and continue heating and stirring until the temperature reaches 72°C (162°F). Use your thermometer to keep your mix at 72°C for 25 minutes, adjusting the position of your pan to help regulate the temperature.
4. Cooling the mix
After 25 minutes, take the pan off the heat and weigh it. If the weight is greater than 850g plus the weight of your pan, place it back on the heat and continue heating for another 2-3 minutes or until you get the weight down sufficiently.
Carefully pour the mix into the zip-lock bag and seal. Place it in the water bath and pour about a tablespoon of salt onto the ice to lower the temperature and cool the mix faster.
Once the mix has cooled to room temperature, place the zip-lock bag in the fridge and leave overnight to age.
5. ROASTING THE BANANAS
Once you’ve allowed your mix to age overnight, you can start roasting your bananas. It’s important to use very ripe bananas; the riper your bananas, the more intense the flavour will be.
Pre-heat your oven to 180°C (356°F). Slice the bananas into small pieces and combine with the brown sugar and sea salt on a baking tray.
Bake for around 30 minutes or until the bananas are nice and brown. Don’t stir the bananas during baking to allow them to develop a nice caramelised layer.
Remove the bananas from the oven and use a fork to break them down into a pulp. Don’t worry if you have some large bits remaining as this will produce nice chunky bits of roasted banana in the ice cream.
Transfer to a bowl, cover with cling film, and once the roasted bananas have cooled to room temperature, place int he freezer for 10 minutes.
6. Churning the mix
Once you’ve allowed the bananas to cool to room temperature, place them in the freezer for 10 minutes. Pour the mix into your machine followed by the bananas.
TIP#6 – Leave the compressor running for about 15 minutes
If you’re using an ice cream machine with an in-built compressor, with the bowl in the machine, switch on the compressor and leave it running for 10-15 minutes before adding the mix. This will ensure that the freezer bowl is as cold as possible when the mix is added, which will contribute to a reduction in residence time.
TIP#7 – Use your thumb to push the dasher against the side of the bowl
If you’re using the Cuisinart ICE 30BC, use your thumb to push the dasher against the side of the bowl as soon as you pour in the mix. This will ensure that the dasher scrapes off the layer of ice that freezes to the side of the bowl. Any ice that is frozen to the side of the bowl will act as an insulator, slowing the release of heat from the ice cream to the bowl and increasing the residence time. Remember that the longer the residence time, the larger the ice crystals will grow and the sandier the texture is likely to be. Goff & Hartel (2013) note that even a very thin layer of ice remaining on the bowl wall can cause a dramatic reduction in heat transfer. The longer you keep the dasher pushed against the bowl wall, the shorter the residence time is likely to be.
Use a spoon to push along any static lumps of ice cream and ensure that the mix is constantly moving whilst in the machine. Static lumps will likely take longer to freeze, giving the ice crystals more time to grow.
7. Extraction time
Your mix will be ready when it develops a nice dry, stiff texture, and starts forming ribbon-like swirls. When you remove the dasher, your ice cream should stick firmly to it.
The point at which your mix is ready for extraction will vary from 14-45 minutes depending on the machine you use. For the Cuisinart ICE 30BC, your ice cream should be ready at around 30 minutes of churning. For the Cuisinart ICE-100 and the Breville BCI600XL Smart Scoop, this should be after 32 and 33 minutes respectively. For the Lello Musso Pola 5030, your ice cream will be ready after around 14 minutes and the Lello Musso Lussino 4080 after about 16 minutes.
Just before your mix is ready, quickly take the plastic container out of the freezer and have a large and a small spoon ready. It’s important that you empty your ice cream from the freezer bowl and get it into your freezer as quickly as possible. The extraction time, that is the time it takes to remove the ice cream from the machine and get into into your freezer, has a considerable effect on ice crystal size. This is because as you extract your ice cream from the bowl and into a plastic container, it spends time at room temperature. At this relatively warm room temperature, some of the ice melts from the large ice crystals and the crystals that were initially small melt completely. When you then get your ice cream into your freezer for the static freezing stage, the melted ice re-freezes onto the large ice crystals that survived. The result is that the total number of ice crystals is reduced and their size increases, the perfect formula for coarse texture.
TIP#8 – Get your ice cream into your freezer as quickly as possible
Just holding ice cream at relatively warm room temperatures as you’re extracting it from your machine results in an increase in mean ice crystal size and a decrease in the number of ice crystals present (Goff & Hartel 2013). It’s therefore important that you extract the ice cream from the freezer bowl and get it into your freezer as quickly as possible.
8. Static freezing
When you finish churning your ice cream, it will be extracted from your machine at around -5°C (23°F) and will have a consistency very similar to that of soft serve ice cream. Ice cream is usually served in its scoopbable state at around -12°C (10.4°F) and so you will need to get your ice cream into your freezer to harden. Because ice crystals continue to grow until the temperature drops to -18°C (0.4°F), ideally -25 to -30°C (-13 to -22°C), the faster you get your ice cream below these temperatures, the less ice crystal growth will occur.
After about 4 hours, depending on your freezer, the ice cream will have a nice firm scoopable consistency, somewhere around -15°C (5°F), and be ready to serve.
TIP#4 (again) – Promote quick hardening
To promote quick hardening, make sure your freezer is as cold as possible when you freeze your ice cream. Place your ice cream at the back of your freezer where it is coldest. Try and clear some space in your freezer when chilling your ice cream. Putting ice cream in a densely packed freezer will reduce heat transfer, resulting in an increase in freezing time.
9. Serving your ice cream
Serve your ice cream at around -15°C (5°F). If you can wait, allow the ice cream to warm to below -12°C (10.4°F) before eating. As the serving temperature is increased from -14.4 (6.1) to -7.8°C (18°F), flavour and sweetness become more pronounced.
10. Storing your ice cream
At -18°C (-0.4°F), it is recommended that homemade ice cream be kept for about a week. Ice cream can be stored for several weeks at -25°C (-13°F), and several months at -30°C (-22°F) (Goff 2012). Even at these low temperatures, however, ice crystals will eventually start growing in size. The longer you store your ice cream in the freezer, the larger the ice crystals will grow and the sandier the texture is likely to be.
Try to minimise the number of times you take your ice cream out of the freezer as temperature fluctuations especially promote recrystallisation during the storage of the ice cream (Donhowe & Hartel 1996). Goff & Hartel (2013) state that temperature fluctuations may be associated with 1. changes of temperature of storage, 2. heat shocks, where ice cream is left at room temperatures for extended periods of time, and 3. opening and closing of doors in freezers and storage cabinets. Changes of temperature of storage are associated with frost-free home freezers where temperatures can vary quite widely during the frost-free cycle (Ben-Yoseph & Hartel 1998). Heat shocks occur when ice cream is removed from the freezer, thawed before serving, and then the unfinished ice cream returned to the freezer.
TIP#9 – Switch off your frost-free setting
If possible, switch off your frost free setting when storing ice cream to prevent temperature fluctuations, which contribute to ice crystal growth.
SECTION 3: QUICK RECIPE
- Fill a large bowl with some ice. Place some table salt and a zip-lock bag next to the bowl ready for later.
- Combine the sugar, skimmed milk powder, egg yolks, cream, and milk in a large pan. Heat over a medium heat until the temperature reaches 71°C (160°F), making sure you are constantly stirring.
- When the mix reaches 71°C (160°F), quickly turn the heat down to low and position your pan slightly off the heat. Continue heating and stirring until the temperature reaches 72°C (162°F).
- Once the mix reaches 72°C (162°F), continue heating for 25 minutes, making sure you are constantly stirring.
- After 25 minutes of heating, carefully pour the mix into the zip lock bag and seal. Place the zip-lock bag in the bowl and pour about a tablespoon of salt over the ice.
- Once the mix has cooled to room temperature, place in the fridge and leave to age overnight.
- The next day, pre-heat your to 180°C (356°F). Slice the bananas into small pieces and combine with 20g brown sugar and 1/4 tsp fine sea salt on a baking tray. Bake for around 30 minutes or until the bananas are nice and brown.
- Remove the bananas from the oven and use a fork to break them down into a pulp. Transfer to a bowl, cover with cling film, and allow to cool to room temperature. Once cooled to room temperature, place in the freezer for 10 minutes.
- Pour the mix into your ice cream machine followed by the roasted bananas.
- After about 35 minutes of churning, depending on your machine, quickly empty the ice cream into a plastic container and place in the freezer for about 4 hours to harden.
- After about 4 hours, your ice cream will have a nice firm consistency and will be ready to serve.
I’d love to hear from you if you do give the recipe a try so do get in touch and say hello! All the best, Ruben 🙂
References
Arbuckle, W.S., 1986. Ice Cream (4th ed). New York: Van Nostrand Reinhold.
Ben-Yoseph E., and Hartel, R. W., 1998. Computer simulation of ice recrystallization in ice cream during storage. Journal of Food Engineering 38(3):309–29.
Cook, K. L. K., & Hartel, R. W., 2010. Mechanisms of Ice Crystallisation in Ice Cream Production. Comprehensive Reviews in Food Science and Food Safety. 9 (2).
Damodaran, S., 1996. Functional properties. In: Nakai, S., Modler, H.W. (Eds.), Food Proteins – Properties and Characterization. VCH Publisher, New York, pp. 167–234.
Donhowe, D. P., Hartel R. W., and Bradley R.L., 1991. Determination of ice crystal size distributions in frozen desserts. Journal of Dairy Science. 74.
Donhowe, D. P., 1993. Ice Recrystallization in Ice Cream and Ice Milk. PhD thesis, University of Wisconsm-Madison.
Donhowe, D. P., and Hartel, R. W., 1996. Recrystallization of ice in ice cream during controlled accelerated storage. International Dairy Journal. 6.
Drewett, E. M. & Hartel, R. W., 2007. Ice Crystallization in a Scraped Surface Freezer. Journal of Food Engineering. 78(3). 1060-1066
Flores, A. A., & Goff, H. D., 1999. Ice Crystal Size distribution in Dynamically Frozen Model Solutions and Ice Cream as Affected by Stabilzers. Journal of Dairy Science. Volume 82. 7. 1399–1407
Goff, H. D., 2012. Finding Science in Ice Cream. Presentation – Royal Canadian Institute for the Advancement of Science.
Goff, H. D. and Hartel R. W., 2013. Ice Cream. Seventh Edition. New York Springer.
Monahan, F. J., McClements, D. J. & Kinsella, J. E., 1993. Polymerization of whey proteins in whey protein-stabilized emulsions. Journal of Agricultural and Food Chemistry. 41.1826–1829.
Phillips, L. G., Schulman, W. and Kinsella, J. E., 1990. pH and heat treatment effects on foaming of whey protein isolate. Journal of Food Science. 55:1116–1119.
Russell, A. B., Cheney, P. E., & Wantling, S. D., 1999. Influence of freezing conditions on ice crystallisation in ice cream. Journal of Food Engineering. 29.
Sava, N., Rotaru, G. & Hendrickx, M., 2005. Heat-induced changes in solubility and surface hydrophobicity of β-Lactoglobulin. Agroalimentary Processes and Technologies. Volume 11. 1. 41-48.
I love this recipe. I marbled in some chocolate fudge and it was perfect. I will reduce the sugar a bit next time as the very ripe bananas contributed so much sugar of their own. Loved it all the same!
Hi Ruben,
I tried this recipe and it was the most delicious ice cream I’ve ever had. It was a rich, unctuous, creamy and thoroughly banana-y taste of heaven. Your recipe is very clear and because of the explanations at each stage, I had an understanding and appreciation of the necessity of each step. The only deviation I took was in using malted milk powder vs. skim milk powder since I didn’t have any of the latter. I think the malted flavour just served to enhance the roasted banana flavour. Thank you so much for this recipe!
~Zoe
Hi Zoe!
It is soooooooo nice to read feedback like yours, makes the late nights writing this blog worth while!
Thank you so much for the kind words and let me know if there is anything I can help with.
All the best,
Ruben
Hi Ruben, Congratulations on your wonderful website.
All the information you are proving is certainly awesome.
I love to make Gelato :), just as you.
I am following few books from famous Italian Masters (who are proving courses for Gelato) but all of them are using stabilizers and sugars like Corn Syrup and Dextrose, which I can not see in any of your recipes.
I did contact the book writer personally, for asking about my doubts about using Corn Syrup but she told me that “it is totally fine“ to use it.
1. What do you think about using such ingredients?
2. Do you think that just using Eggyolk instead of stabilizer, is sufficient?
3. For how many days your ice cream remains smooth?
4. How many days after production ice crystals start to grow and you no longer would like to serve your product?
For sure it is wonderful to use Natural ingredients but on the other hand, such ingredients are inside everything we are consuming nowadays. It is almost impossible to avoid consumption without gums or corn syrup.
I know that these ingredients help to emulsify and Stabilise the recipe. As a result, we are getting a very smooth texture and much longer shelf life.
Personally, I can say that I am confused about what is correct or wrong. It seems very difficult to maintain everything totally artisanal while, on the other hand, it is annoying to use ingredients which seem not good for the human health.
Personally, I think that the answer is between “Quality” or “Quantity”. But unfortunately, it seems like the world is running after quantity.
I will appreciate your comments.
Thank you.
Hi there Mose!
Thanks for getting in touch and apologies for the delay in getting back to you. I’ve just seen that you’ve also e-mailed me.
Your message is perfectly timed as I am currently having some trouble increasing production without having to add extra ingredients! My opinion is that it is easy to make SMALL AMOUNTS of excellent ice cream using just milk, cream, sugar, and egg yolks. However, when it comes to making large amounts of ice cream, I’ve found that I’ve had to add skim milk powder to my recipes as I haven’t yet figured out a way to evaporate enough water from a large 7 litre batch to increase the percentage of not fat-milk-solids.
Here are the answers to your questions:
1. glucose syrup is a naturally-derived ingredient but it is heavily processed. Sucrose (sugar) and skim milk powder are both naturally-derived ingredients but, again, are processed. I’ve read some literature on the health implications of high fructose corn syrup, which is made in the same way as glucose syrup. I personally don’t like consuming foods with glucose, fructose, or dextrose sugars added as these ingredients are usually, although not always, synonymous with low-quality food. Because I don’t like eating them myself, I leave these sugars out of my ice cream. I think there is also a perception, possibly wrongly held, that sucrose is in some way superior, more healthy, or not as bad for you, as glucose syrup.
2. Egg yolk and stabilisers have different effects in ice cream production but yes I do think it is possible to make excellent ice cream without the use of stabilisers. I don’t use stabilisers or emulsifiers in my ice cream.
3. This depends on the flavour. I’ve found that ice cream with a high solids content (pistachio, hazelnut, almond) stays smooth and creamy for 4-5 weeks (I haven’t tested any longer than this) at -25°C. Ice creams with a lower solids content (vanilla) remain smooth and creamy for slightly less time.
4. This is the same as the answer to question 3.
I hope that answers your questions. Let me know if you have any more.
All the best to you,
Ruben
Hey Ruben,
Many thanks for your blog and the recipes. I absolutely love ice-cream and your blog was reason for me to buy the Musso ice-cream machine. First I made some frozen yogurt, according to a recipe I found on the internet. It tasted awful, so I was hoping it wasn’t the machine. Second I made your Roasted Banana recipe, which was the most creamiest, fresh and best tasting ice-cream ever. I did everything exactly how you described. The ice-cream was absolutely amazing. Thank you so much for al your work and testing, and giving us this information for free. It is of great value to me. I am also happy with the recommendation to buy the Musso. Sorry I couldn’t use your amazon link, because I live in The Netherlands.
I am still studying all the info on you website, but I have a question if you don’t mind. I used white refined sugar, because I can’t find unrefined sugar in The Netherlands. Does this affect the ice-creams texture? And I thought, although the ice-cream was amazing, that it was a little bit too sweet. Could that be because of the refined sugar? Next time I am planning on making the chocolate ice-cream, but I will use a little less sugar because I like it a little less sweat. I hope it won’t affect the texture too much.
Much thanks.
Kinds regards,
Menno
Hi there Menno!
Thanks for getting in touch and a big hello to you in the beautiful Netherlands. Great to hear that your roasted banana ice cream turned out well, albeit a little sweet. Using white sugar won’t affect the texture because it has the same solids content as unrefined sugar. There will be a slight difference in taste because of the molasses in unrefined sugar. White sugar is also slightly sweeter because of the higher sucrose content so using that instead of unrefined and brown sugar will make the ice cream a little sweeter yes. If you use white sugar next time, half the amount you use on the bananas. You can also reduce the sugar content in the mix by 10g and this shouldn’t affect texture.
I hope that answer your questions. Let me know if you need help with anything else.
All the best to you in The Netherlands,
Ruben
Hey Ruben,
Many thanks for your reply and help! There is a second question I hope you can help me with. You mention that it takes about 25 minutes at 72 degrees celsius to reduce the mixture from 1000 to 850 grams. But for me it takes much and much longer. I keep the temperature at 72 degrees, but after 25 minutes the mixture is only reduced by about 25 grams. I think tonight after 70 minutes it reduced about 75 grams, so it was still 75 grams too heavy, but i didn’t feel like whisking anymore. Do you have any idea why it takes so long for me? I keep whisking the whole time. My pan has a diameter of 21 cm.
Many thanks again.
Best regards,
Menno
Hi again Menno,
Wow, 75 grams after 70 minutes of heating doesn’t sound right. I’d recommend using a larger pan and stirring your mix slightly faster. Both of these will increase the rate of evaporation.
You could also use my spreadsheet and just adjust the figures to adjust for your 25g of reduction after 25 minutes. I’d be happy to help with this if you want to try it.
All the best,
Ruben
Hello Ruben. I love your site. I have yet to make my first ice cream, but I am so excited. I also have a question:
“Once the temperature reaches 71°C (160°F), turn the heat down to medium-low, move your pan slightly off the heat, and continue heating and stirring until the temperature reaches 72°C (162°F). Use your thermometer to keep your mix at 72°C for 25 minutes, adjusting the position of your pan to help regulate the temperature.”
Am I supposed to keep stirring for 25 minutes? I would assume so, but I just want to be sure 🙂
Hi there Sune!
Thanks for getting in touch. Yes it’s very important that you keep stirring the mix for 25 minutes once you reach 72°C. This is to make sure that you achieve the 15% reduction in the water content of the mix for the roasted banana recipe, and also to promote reversible protein denaturation, which has a significant effect on texture. You might need to heat for a few minutes more, depending on the size of the pan you use, if you don’t reach a 15% reduction after 25 minutes heating.
I hope that makes sense. I’d be happy to help if you have any more questions. Please do let me know what you think of the recipe if you do give it a go 🙂
All the best,
Ruben
I just made the base for the first time. Unfortunately my thermometer was all over the place, and I’m pretty sure I heated it way above 72 degrees 🙁
Can you recommend a thermometer to monitor the heat in a pan?
Don’t worry if the temperature briefly goes 2-3°C over 72°C, just don’t keep the temperature higher than 72°C for a long time. You can use any food thermometer, what is more important is moving your pan about half way off the heat when you get to about 69°C and then slowly continuing to 72°C. Keeping about half of your pan off the heat and moving it slightly during heating is a much easier way to regulate heat than focussing on the thermometer.
Hope that helps! 🙂
Thanks. Your help is appreciated 🙂
Actually it is worse than that. I heated up to 69 degrees and then turned down the stove and tried taking the pan a bit on and off. The temperature would constantly fluctuate between 60 and 75 degrees. The problem is when I put the mix in a bag I used the thermometer again, and it showed 80 degrees… That’s why I think it has been overheated. It’s also thicker than I expected. I’ll keep going tomorrow with the bananas and see how it ends up. I might as well make all the mistakes in my first batch 🙂
🙂
Hi Ruben
Have you tried incorporating the roasted bananas to the base itself? I have done this with non-roasted bananas and pushed them over a fine mesh sieve to remove the small seeds. What I’m wondering is maybe, once it’s roasted, it might have lost all the water inside and will be too dry to strain? What do you think?
PS: Glad you have been posting more often 🙂
Hi there Jason!
Many thanks for getting in touch. I haven’t tried incorporating the bananas to the base as I suspect this won’t have a favourable effect on texture. Give it a go and see how it compares to adding the bananas at the end.
If you do add the bananas and leave them in the mix overnight, I would recommend leaving them in and not straining as this is likely to give a stronger flavour.
Hope that helps. Let me know if you have any other questions.
All the best,
Ruben
Hi Ruben, I was wondering if you ever tried limiting the sugar amount in the base. I know its there to keep the egg yolk from curding. Just trying to subtract some calories. I know the taste will change, what about the texture?
Also, I am making mine with fresh goat milk from our goats, so the milk has 3.5% fat in it.
Hi there Christian!
Many thanks for getting in touch! You can indeed reduce the sugar content but you will have to compensate by increasing either the cream, skimmed-milk powder, or egg yolks to ensure that the total solids content remains at around 50% after reduction. Any lower and I find that the texture isn’t as smooth and creamy.
The sugar content also reduces the freezing point, making the ice cream softer, so reducing it might make the ice cream slightly harder.
Send me the fat content of the cream you are using and I will try and put together a recipe using your 3.5% fat goats milk and around 14.2% sugar after reduction.
All the best,
Ruben
Hello again!
I wrote earlier about using clotted cream as a substitution somewhere in this website and since i am experimenting, this time i used “clotted cream”- specifically kaymak(*)- to substitute some of the usual heavy cream. It has 60 percent fat and because of that i added more milk to the recipe to balance. It melts pretty good in the heating mixture although not as perfect as heavy cream. Final product is more strong on the fat side and i believe fat molecules are more dominant and holding. However this makes the ice cream too rich and brings a too flavorful fat/dairy taste. The taste of dairy fights with the main flavour(in this case banana). It’s still very delicious but i don’t know, i think i will stick to heavy cream when making ice cream with additional flavours. But it shouldn’t set you back to use clotted cream (or kaymak) as a flavor on its own. I will try that later and write here my impressions about it.
Other than that the flavour of banana was incredibly tasty in this recipe. It’s even better with added chocolate particles (30 grams of 70 percent cocoa chocolate).
Yeah that’s about it, wishing a fun summer to everybody!
(*)https://en.wikipedia.org/wiki/Kaymak
Hi again Alp!
Chocolate and banana is now on my to-make list!
All the best,
Ruben
I would like to ask about the commercially available ice cream in the market and what type of preservatives do they use? If only you know and if possible can I use it so that I can have my ice cream stored in a longer shelf life?
Hi there Alyssa!
Thanks for getting in touch. Commercial ice cream makers use stabilisers to increase shelf life by retarding ice crystal growth. I haven’t used stabilisers myself but have a look at my post on why stabilisers are used in ice cream making for an idea of the ones you can use.
I hope that helps. Let me know if you have any other questions.
All the best,
Ruben
Erik
I actually just finished Churning your Salted Caramel recipe. I added 2 tsp. Corn Starch to see how it turns out.
Hi Erik!
I’ve never tried using corn starch so please do let me know how it turns out!
Erik
Will do but since this is my first time using your recipe I don’t really know how it’ll compare to had I not used the starch.
Also I’ve read somewhere, I can’t recall where, that to activate the cornstarch you should cook it at 170F degrees for about a minute and I never got that high when I used your recipe. Stayed at around 71-73C. Maybe next time I’ll heat the starch separately and then add it in to the mixture that heats at 71-73C (side not: I forgot to mention that it was tapioca not corn, but same thing).
🙂
Erik
Just saw this site today and am really enjoying going through everything. I’ve got a few questions
1.) Typically about how many grams does yolk weigh in one large egg?
2.) I’ve noticed that in your older recipes you would cook the mix for an hour but have now reduced it to 25 minutes. Does it depend on the recipe or should we do 25 minutes of heating for your older recipes as well?
3.) Why skim milk over whole milk? I’m assuming it has to do to do with the fat ratios?
4.) And lastly, do you have any coffee flavored recipes?
Hi Erik!
Thanks for getting in touch! Hope the blog helps.
Typically, a large egg yolk in the U.K weighs 17g. This will invariably change depending on where you are in the world. Where in this world of ours are you writing from?
I’ve changed my recipes to the new 25 minute heating method because the feedback I got on the old 60 minute method was that it simply took too long. I’m in the process of updating the older recipes. Don’t use the 25 minute heating method on the old recipes with the old quantities as these won’t give the desired texture.
The only reason I use skimmed milk is to standardise the recipes for folks around the world. You can use either skimmed or whole milk but the cream quantity will be different if you use whole milk t reflect the increase in milkfat in whole milk.
I worked on perfecting a coffee recipe a long time ago but haven’t managed to get it up on the blog yet. It is now on my to-do list.
Hope that helps. Let me know if you have any other questions.
All the best,
Ruben
Humayun
Hey!
I love making ice cream from your recipe’s but here in Pakistan i can only find creams at 30% fat and milk at 3.5% fat. Till now what i’ve been doing is, seeing which ingredients you change when your fat content increases for the cream and take it the other way round with an estimate. If you have an exact formula, i’d love that =D
Also thanks for all the recipes! =D
Hi there Humayun!
A big hello to you in Pakistan!
If you are using cream at 30% and milk at 3.5% fat, use this recipe to make your base mix for the roasted banana ice cream. Heat it at 72°C for 25 minutes. You should be left with about 850g after heating. Then add the roasted bananas.
Cream 650g
Milk 86g
Skimmed milk powder 46g
Sugar 140g
Egg yolks 78g
Let me know how your ice cream turns out.
Hope that helps.
All the best,
Ruben
humayunharoon
Hey Hey! Once again! =D I tried the recipe out and everyone simply loved it like anything! I took half the batch to my office and my mates literally licked the container clean :p Kudos to your recipe =D
Alright, so i was just going to ask the 60mins to 25 mins shift, but someone had already asked it, and yeah 60 mins of cooking in Pakistan’s summers is killer :p I like the change.
One/few :p more questions, can i also ask for quantities for 30% cream on your other recipes when making them?
Also, sometimes i wanna experiment with different chocolates or fruits, can you like recommend a generic base (the quantities) for experiments like these? Thanks
I’m trying to find natural vanilla these days so i can try out your new recipe! =D =D =D
Hi again Humayun!
Great to hear everyone liked the recipe!
Here are the quantities for a 1000g mix if you are using cream at 35% fat and skimmed milk at 0% fat:
Cream 566g
Milk 170g
Skimmed milk powder 46g
Sugar 140g
Egg yolks 78g
You should be left with about 850g after reduction. I would recommend the above mix for a generic base that you can then add chocolate or fruit to. If using fruit with a high water content, you might need to heat it to reduce some of the water.
Hope that helps. Let me know if you have any other question.
All the best to you in Pakistan,
Ruben
Hello Ruben. I know most ice cream shops use pre made ice cream bases but how do they infuse such flavors? i know cold infusing wouldnt be as strong as infusing them in hot cream/milk like shops with pasteruizers do.
Hi there Chul!
Thanks for getting in touch. Ice cream shops that use pre made base mixes will either use artificial flavours or will add the natural flavour directly to the machine after the base mix. I don’t know whether ice cream shops that use pre made base mixes are permitted to infuse the cold mix overnight or are allowed to re-heat it after infusion.
Hope that helps. Let me know if you have any other questions.
All the best,
Ruben
Hello Ruben,
Thank you for your information about the recipe, i always like to read your article because you always give the science explanation behind every things you do when making the ice cream.
i got a little confused about style of making ice cream,
you always use egg yolk (french style) for making ice cream right?why you never try not to use eggyolk but try to use the starch, cream cheese, and corn syrup (philladelphian style), because some said philladelphian style are less calories, more healthy and it become more popular in the last two year.
could you help me by explain my question?
thank you for your time.
Hi Victor!
Many thanks for getting in touch. I use egg yolks in my recipes because I have found that ice cream made with yolks has a smoother and creamier texture than ice cream that does not contain yolks.
The ice cream that I make for my business is made using only cream, milk, sugar, and eggs. I don’t want to use any artificial or excessively processed ingredients and so do not use corn starch or syrup. I know that the Jeni’s Splendid Ice Creams book has recipes that use cream cheese and corn syrup so maybe you can give that a go.
I hope that helps. Let me know if you have any other questions.
All the best,
Ruben
Anonymous
Victor,
Cream Cheese used in ice cream can be delightful if done right. The texture comes out chewy and has a nice tang. Cream cheese is chock full of milk proteins so there is no need for milk powder and you can do without eggs (making a Philly-style ice cream) and it has much less water. You must keep the fat content (and water) in mind when using and keep everything balanced. Check the brand you use but it should be around 33% (in the US anyway). Cream is more like 40%. Anyway, i find that substituting 35 to 40% of the cream with cream cheese works well in an egg-free (Philly) recipe but you should calculate total butterfat, water, and MSNF (proteins) and make sure they fall within the desired ranges. And you need to let the cream cheese get to room temp to be able to work with (cut up the cheese and put it in a bowl on the counter covered before you start cooking) and whisk it in the chilled base and then blend together until completely smooth (a minute or so in blender on high works fine) before putting in the fridge to cure. corn syrup is highly processed but, if you can find it, glucose syrup substituted for 25%of the total sugar is awesome for texture!