Egg-free frozen yogurt advice
I've been trying to use corn starch to make egg-free frozen yogurt.
My usual procedure is:
1 L full-fat yogurt
1/2 cup sweetened condensed milk
1 cup half-and-half
2 tbsp corn starch and 2 tbsp water mixed well
Heat up 1 cup of the yogurt + half-and-half + condensed milk, add corn starch solution, stir until boiling and thickened, mix with the rest of the yogurt, let cool in fridge, then pour into electric ice cream maker.
I find though that my results still
(1) freeze like a rock after putting in the freezer -- I have to take them out and let thaw several minutes before it's possible to scoop, unlike all the egg-free commercial frozen yogurts out there.
(2) I have this slight unpleasant powdery texture in the mouth after eating, presumably from the corn starch.
What's the secret to all the egg-free store-bought ice creams? and is there anything other than corn starch I can use without resorting to eggs, to avoid that powdery texture? If I add any less corn starch, I get a mess of ice crystal texture.
Hum. That recipe just looks weird to me. Most frozen yogurt recipes don't require egg so I am not sure why you are trying to "replace" it. I personally like the Patricia Wells version, which is somewhat like Pinkberry in flavor. I generally use a higher fat yogurt than she specifies.
Are you actually trying to make mock ice cream?
I believe the Patricia Wells version requires egg, which I'm trying to avoid. The idea is usually to reduce the formation of ice crystals. Most ice cream recipes use either egg or corn starch or alcohol to prevent the formation of crystals, so I was trying to do the same with frozen yogurt.
I make froyo at home quite a bit and have never used eggs.
All you really need are whole milk yogurt and whole milk, and whatever fruit fillings you want to add, and maybe some additional sweetner like honey or sugar.
The powdery texture you are getting is no doubt from the corn starch. I wouldn't use corn starch. It adds nothing, except for a "powdery texture" ...
Hmm thanks. I'm using corn starch for the same reason ice cream needs an emulsifier (like egg or corn starch).
I tried once without too, but once put back it in the freezer, it turns very hard and forms ice crystals all over inside, ruining the texture. It never comes out creamy like you get in those frozen yogurt stores. If I add starch it comes out creamy (no crystals, and scoops well after freezing) but then I get the nasty after-texture in the mouth... Any thoughts? I'm just trying to figure out what it is that those commercial people are doing makes it creamy and store well in the freezer.
I've never put egg in frozen yogurt. If you use a full fat yogurt, the frozen product will be more scoopable. Alternatively, you can include a tbsp. or two of vodka to keep low fat yogurt from freezing rock hard. There are good recipes, all egg free, in David Lebovitz' The Perfect Scoop as well as in Cook's Illustrated. The CI recipes use gelatin and are reliably smooth in texture, though a bit more involved and not as clean tasting. Personally, I prefer Lebovitz' recipes these days. His tart fro yo recipe is online with the LA Times: http://www.latimes.com/features/food/...
Patricia Wells recipe has egg white merinque because she uses non-fat yogurt. Egg yolks are not necessary to make smooth/non icy frozen yogurt/ice cream. American style and most gelato contain no eggs. What is needed are fat and sugar. Honey does wonders for creamy soft consistency. Many brands of full fat yogurt have too much water. Straining it will remove needless water or use a full fat Greek style yogurt. For me, there is no better or easier recipe than the one by David Lebovitz mentioned by earlier posters. It has three ingredients: strained full fat or Greek style yogurt, sugar and vanilla extract.
Sugar, alcohol, and salt all lower the freezing point and contribute to a softer frozen product (fats and milk solids also play parts). The sugar in a half cup of SCM is likely not enough to keep 5-1/4 cups of yogurt and half and half soft. Try more SCM, or a bit of honey or other sugar, or a TB or two of liqueur.
I am surprised the yogurt doesn't curdle when you bring it to a boil. Are you sure the grainy bits aren't curdled yogurt? It is possible to use cornstarch as a thickener, see Mark Bittman's corn starch ice cream, but I don't think you necessarily need it for frozen yogurt. I have experimented with it and not found any grittiness.
re: babette feasts
Well, I only just let the corn starch and a little bit of it thicken up, and then once it starts to thicken, quickly mix it with the rest (most) of the yogurt so it (1) doesn't curdle and (2) keeps the cultures alive for health.
As a vegetarian I must avoid gelatin; alcohol is an option but I don't usually have strong alcohols like rum and vodka lying around :-/ Sugar alcohols are another option but I do want to try to be able to control what sweeteners I use if possible -- some recipes call for honey and no sugar, for example.
What about food-grade glycerine and/or xanthan gum (used in some commerical ice creams, I think) and I might be able to obtain these locally. Would they suit frozen yogurt? Also, would arrowroot or wheat starch work better than corn starch? There are plenty of Chinese stores here where I can get these starches.
I would stay away from starches entirely. They're just unnecessary. You don't need gelatin, either, if it doesn't work for you.
With the full fat yogurt and half and half in your original recipe, you should have enough fat, but consider adding more sugar than what's in your condensed milk. I haven't had much luck with sugar alcohols resulting in good texture, with the exception of maltitol syrup. It's not easy on my stomach, however you may not have the same experience.
Can you buy alcohol in small quantity? Just a tbsp. or two with the same recipe containing just the condensed milk for sweetener may be enough to get a scoopable frozen yogurt, if you really don't want to add more sugar.
Thanks everyone for all the suggestions!!
So, I did a little research about this, looked up all the ingredients in various commercial brands and then tried to roll out my own new version with what I could get easily. Here's my new recipe:
1 L full-fat yogurt
250mL Greek yogurt
1 tsp Xanthan gum (stabiliser)
1 tbsp food-grade Glycerin (freezing point depressor)
1/4 cup Xylitol (freezing point depressor and sweetener)
1/4 cup sugar
1 tbsp lime juice (adds some tartness)
This worked almost to my liking -- I now get a nicely scoopable frozen yogurt, but it still has some ice crystal texture and is flaky rather than creamy when scooped. Perhaps I need to add more gum or add more fat (maybe full cream instead of half-and-half, or put back the condensed milk into the recipe?) or emulsify it with something, perhaps add a very tiny amount of starch water and thicken? (pinkberry uses starch of some sort, actually ... not sure what kind)... otherwise, seems like it's making some progress :) Hopefully next round I should get this right.