A physicist's guide to ice cream
10 comments
·January 16, 2025Xmd5a
I started cooking ice cream this summer. I bought an ice cream machine that can yield 1L of ice cream in 30 minutes, and prepared about 30L, sometimes sourcing material from the garden (strawberries, raspberries, cherries, figs and blackberries). If you enjoy the taste of fresh figs (which I don't normally because of the texture of the fruit) it is an incredible way to preserve it.
The best ice cream I made was blueberry + coco cream + lime. Highly recommend it. Coco cream as a substitute for water in sorbet is an amazing trick.
Shared this with a friend yesterday:
1. **Creaminess (smooth, creamy texture)**
Creaminess ↑ ⇔ Cream ↑ + Eggs ↑ + Sugar ↑
Creaminess ↓ ⇔ Water ↑ + Fresh fruits (high in water) ↑
2. **Lightness (airy texture)**
Lightness ↑ ⇔ Milk ↓ + Cream ↓ + Eggs ↓ + Sugar ↓
Lightness ↑ ⇔ Air incorporation (whipping) ↑
3. **Stability (avoiding crystallization)**
Stability ↑ ⇔ Sugar ↑ + Eggs (yolks) ↑ + Alcohol ↑
Stability ↓ ⇔ Water ↑ + Uneven freezing temperature ↑
4. **Density (weight in the mouth)**
Density ↑ ⇔ Fats (cream, butter) ↑ + Eggs ↑ + Sugar ↑
Density ↓ ⇔ Incorporated air ↑ + Water ↑
5. **Melting Temperature (softer or harder out of the freezer)**
Melting Temperature ↑ (softer) ⇔ Sugar ↑ + Alcohol ↑ + Air ↑
Melting Temperature ↓ (harder) ⇔ Water ↑ + Freezing temperature ↓
6. **Sweetness (perceived sugar)**
Sweetness ↑ ⇔ Sugar ↑ + Sweet fruit puree ↑
Sweetness ↓ ⇔ Acidity (lemon, vinegar) ↑ + Acidic fruits ↑
7. **Crystallization (grainy or smooth texture)**
Crystallization ↑ ⇔ Water ↑ + Poorly mixed ingredients ↑
Crystallization ↓ ⇔ Fats ↑ + Sugar ↑ + Proper agitation ↑eleveriven
Have you tried incorporating herbs (like basil with strawberries)? Or you do not like that kind of things?
Xmd5a
Yes, I have, and this is a bad idea (strawberry + mint). The problem is that the herbs become harder than the ice cream, creating an unpleasant sensation in the mouth. I had a similar issue with a toffee ice cream where I tried incorporating small cubes, but they became too hard when frozen.
One possible solution could be to candy the herbs (though it’s a lot of work) or to soften the toffee by turning it into a kind of cream, freezing it separately, and then folding it into the ice cream at the last moment. This challenge is addressed in the article,
>We need to add sugar to the fruit to make sure it is softer than the ice cream itself – you don’t want to bite into ice cream and find a hard, frozen berry.
and considering you almost never see artisanal ice creams with chunks (unlike industrial ones like Ben & Jerry’s, for example), this is where culinary engineering becomes essential I guess.
seec
If you don't care about having the bits for texture and only care about the taste you could infuse the cream. Heat the cream (stop before boiling of course), add the bits, let it rest for a while and then sieve it. I will add some time but it should work.
I'm also not a fan of ice cream with solid stuff. If you can't lick it pleasurably, it's not really ice cream in my book.
rokkamokka
Perhaps if you grind the herbs very finely they'll disperse better in the ice cream
holowoodman
The best ice cream recipe ever I got from a physicist:
Cream + sugar + vanilla, stir until dissolved. Slowly add liquid nitrogen while stirring fervently until sufficiently frozen.
The stirring in of the liquid nitrogen not only freezes the cream, it prevents any cristallisation and fluffs up the ice cream by evaporating. Truly delicious!
oakwhiz
I can confirm that this works and is delicious.
Theodores
my view of ice cream has changed over time. I grew up close to the biggest factory for ice cream in the UK where it was adjacent to the biggest bacon factory in the UK.
The myth at the time was that the fat from the bacon went next door to the ice cream factory. At the time the label just said 'animal fats' rather than 'dairy' so there was nothing to dispel the myth.
Since then the formulation has changed, now you get the usual palm oil. As far as ultra-processed foods go, is there anything worse than commercial ice cream? You have got animal fats or palm oil to block your arteries, refined sugar to spike your glucose and lots of emulsifiers and other 'e numbers' to disrupt your digestive tract?
Most ice cream is sold in tourist venues where the vendor knows he will never see the customer ever again. There is zero motivation to make it a healthy product or to use quality ingredients when you are not expecting repeat customers.
In other developments, there is a move to have more efficient freezers for ice cream in stores, which means changing the temperature so it does not need to be stored at such a low temperature. The likes of Unilever can spend a fortune on the food science to get the temperature up, to roll out new freezers.
My local supermarket only sells the basic flavors vanilla, strawberry and chocolate. But then they sell dozens of variants of Ben and Jerry's and similar brands. I wish this was the other way around. Just give me boxes of single flavors like in the Italian gelaterias.
I guess supermarkets get higher margins on B&J's.