Why does my ice cream have a grainy texture?
I made two ice creams this weekend, one French vanilla based custard with cream, milk and egg yolks and the other was chocolate with whole eggs and 1/2 and 1/2.
I have the basic model Cuisinart
and the bowl had been frozen over 24 hours.
The bowl was quite full for each and I took it off at 25 minute mark and it was a bit slushy. Sort of soft peak whipped cream texture.
Any tips for ultra smooth ice cream would be most appreciated.
Make less at a time and don't let the machine run for so much. But bear in mind that homemade ice cream will never be as smooth as storebought, simply because you don't have a commercial power churning device.
Martha Stewart's recipe for vanilla ice creas is pretty loved on this board, and my friends have said they like it better than Hagen Daaz despite the slightly less creamy texture (very slight).
Homemade ice cream, with the right ingredients, can be as smooth as store bought. Soluble fiber gums like xanthan and guar (available in health food stores) promote smaller ice crystal formation. Invert sugar provides superior freezing point depression (with a lower freezing point you have less ice to make crystals). Lastly, lecithin is available to the home cook. Lecithin helps create a better emulsion, breaking down the water and fat into smaller units. With smaller units of water, you end up with smaller particles of ice.
And yes, the less base in the machine, the faster it freezes. The faster it freezes, the smaller the ice crystals. I agree with you there.
Was the custard cooked to around 170 degrees? If you undercook, the eggs don't bind to the other ingredients and your custard won't be smooth. If you overcook, the eggs become scrambled and dry and the mix will be curdled. I think either case will result in grainy ice cream.
I usually take my custards off heat when they are around 160 and keep beating and watching the mix to make sure it's thickened and smooth.
I think the slushiness gives it away...your bowl didn't stay cold enough. I would either reduce the batch size (perhaps by as much as 1/3, assuming your description of 'fullness' was at the start of the churn and not at the end), or check the temperature of your freezer to make sure the bowl is getting cold enough.
I add a tablespoon of vodka to all frozen treats I make in my Cuisinart ice cream maker (my machine makes about a quart at a time). The alcohol in the vodka lowers the freezing point of the mixture so that there's more time to break down the crystals. The vodka imparts no flavor. I've heard that Cobasan, the whipped cream stabilizer, is a wonderful addition, but I don't have any in my pantry. I use a teaspoon of glucose instead. You could probably use corn syrup if you don't have glucose.
someone can chime in here with the food science of this, but, if cream/milk isn't heated to a high enough temperature there is something in it (protein? enzyme? alien stowaways?) that makes for that familiar homemade bumpiness of ice cream. If you heat the milk/cream up to a good 170 or 180 then it "kills" whatever it is in the dairy products that inhibits its ability to get that creaminess to it and you get really smooth ice cream.
On the heating of the milk - I heat it up to 185. but, and this is an important one - if it is a custard (i.e., egg) based one, you obviously have to do that before you add eggs, since they can't be taken much above 175 without getting eggy...
Anyhow, not sure if that is what you are describing, but if it wasn't heated that high, it could be a culprit, as could be some of the other things people mentioned - like the freezer bowl not being cold enough, thus not able to churn properly.
Bringing the milk/cream to a boil first changes the way it acts in ice cream.
From Harold McGee's On Food and Cooking:
"In boiling milk, unfolded lactoglobulin binds not to itself but to the capping-casein on the casein micelles, which remain separate; so denatured lactoglobulin doesn't coagulate. When denatured in acid conditions with relatively little casein around, as in cheese whey, lactoglobulin molecules do bind to each other and coagulate into little clots, which can be made into whey cheeses like true ricotta. Heat-denatured whey proteins are better than their native forms at stabilizing air bubbles in milk foams and ice crystals in ice creams; this is why milks and creams are usually cooked for these preparations (pp. 26, 43)."