Thursday, June 20, 2013

Better Living Through Chemistry

Vegan Green Tea Ice Cream
OK, now we're getting somewhere!  This last batch was much better.

In retrospect, I did a number of things wrong with my vegan chocolate ice cream.  In dairy ice cream you're supposed to heat it for a while to denature the whey proteins and improve the smoothness of the finished product.  Jeni's recipe boils the mixture for 4 minutes, while Ice Cream Science suggests an hour!  (Ice Cream Science also suggests a precise temperature to avoid bringing out an eggy flavor, but that's not an issue with the recipes I'm using.)  I only heated mine up to a boil, as suggested in Vegan Scoop.  Do soy proteins denature in the same way?  Maybe not, but it seems likely there is some benefit.

In addition, the base should be boiled with as few solids and flavor ingredients as possible, party because boiling tends to mute the flavors and partly because it impedes denaturing the proteins.  I dumped everything in before heating my base.  Whoops.  Jeni's book also warns that adding chocolate directly to the base can cause a dry and crumbly texture, but I think this may be less an issue with soy-based mixtures than with dairy.

I added a few ounces of brewed coffee to it as well, as suggested in Jeni's Darkest Chocolate Ice Cream in The World recipe.  That seems like a big mistake: adding water to my ice cream base!  Most of the steps in making ice cream are about controlling or reducing the water.  In Jeni's recipe the coffee is used to make a chocolate syrup that gets mixed into the base, but it still seems crazy to add water.

So, for my most recent batch, I addressed many of these mistakes.  I decided to make another vegan flavor.  This time I chose green tea, since it seemed like it would be taste more in context with the soy milk flavor.  I boiled it for 4 minutes with the sugar, and then in a blender I added the matcha, arrowroot, and my new secret ingredient, xanthan gum.  (Using a blender may not be necessary but it was suggested for incorporating xanthan gum on some discussion boards.)

The base churned up nicely and definitely held more air than the previous recipe.  After freezing, it is very smooth, with no detectable ice crystals, and easy to scoop.  It still seems a little dense to me.  I think I will try increasing the mixer speed (aka "shear strength") to incorporate more air ("overrun"), and maybe cut back the xanthan gum from 1/2 tsp to 1/4 tsp.  It's almost too smooth now.

Jeni warns that using too much corn syrup can make the ice cream "soggy" but I can't even get my head around what that means, and I haven't noticed an effect like that.

I think my next experiment will be a test of dairy-based ice cream with the xanthan gum and a faster mixing speed.

Vegan Green Tea Ice Cream Recipe

NOTES: I think this was slightly too much matcha.  It's just a little gritty.  Maybe 4 tsps would be better.


  • 2 cups soy creamer
  • 1 cup soy milk
  • 1/3 cup sugar
  • 1/3 cup corn syrup
  • 1/4 tsp salt
  • 2 tbsps matcha powder
  • 1 tbsp vanilla extract
  • 2 tbsps arrowroot powder
  • 1/2 tsp xanthan gum


  1. Put soy creamer, soy milk, sugar, corn syrup, and salt in a saucepan.  Bring to a boil and then allow to boil for 4 minutes.
  2. Transfer to a blender.  Add matcha and vanilla extract and blend to combine.  Add arrowroot and blend.  Add xanthan gum and blend.  (Be very careful about blending hot liquids!  I keep the small plastic cap off and cover that hole with a dish towel so that it's not air tight.  That prevents the pressure from building up in the blender.)
  3. Pour mixture into a container.  Let it sit until it reaches room temperature (or put it in an ice bath if you're worried about bacteria) and then put it in the refrigerator overnight.
  4. Freeze in an ice cream maker.


  1. Sounds interesting...did I ask if you wanted the ice cream maker from FL? Unfortunately, it's big and heavy.

    1. Is that an Il Gelataio, with the built-in freezer? We have an old one in Maine that I still use when I'm there. It does weigh a ton.

      I think I'd like to have it (it would get the Kitchen Aid freezer bowl out of our freezer), but if it's difficult to ship, don't worry about it.