Sunday, June 23, 2013

Coffee Bourbon Ice Cream and Overrun

Coffee Bourbon Ice Cream
I decided to switch back to dairy ice creams for this one.  I used my current standard low-fat ice cream formula but added in a tiny bit of xanthan gum to see how it would affect the texture.  Of course I also used 1/4 of bourbon (Woodford Reserve, since it was only $3 for this amount!), and that probably had more of an effect on the texture than the xanthan gum did.

My main experiment this time was to try increasing the speed of the beater ("shear strength") to whip more air into the mixture ("overrun").  That failed pretty badly.  I increased the mixer speed one notch and let it go for about 20 minutes, but the mix never took on much volume.  It looked to me like the increased speed prevented it from freezing and without freezing it can't hold the air bubbles.  (Is that crazy?  Maybe the increased volume in my mixes is normally due to ice crystals forming.)

I finally gave up and ran it at the lowest speed as usual, and then it bulked up as much as it usually does, which is to say not much.  The final result is tasty and smooth, and very soft and scoopable, but still too dense.

So, what to try next in my quest to increase overrun?  I have two ideas:

  1. Get the mix colder before putting it into the freezer.  I may have chosen badly by doing a flavor with alcohol in it, since that depresses the freezing point already.  If I try a non-booze flavor, and maybe put it in the freezer for 15 minutes before spinning it, it might freeze well even at the higher speed.  Or it might seize up and break my ice cream machine.
  2. Use more thickeners to increase the viscosity of the mix so that it can hold more air bubbles.  I cut back my use of cornstarch a bit because I felt like I could taste it in my vanilla, but I could use more in strong flavors like chocolate and coffee, or switch to a mix of guar gum and xanthan gum so that I use a smaller proportion.

Coffee Bourbon Ice Cream Recipe

NOTES: I like to see little flecks of coffee bean in my ice cream, so I just use a fine mesh strainer to remove the coffee grounds.  If you want to get it pristine, use cheesecloth.


  • 3 cups fat free half and half
  • 1/3 cup sugar
  • 1/3 cup corn syrup
  • 1/4 tsp salt
  • 2 tbsps corn starch
  • 1/4 cup neufchatel (1/3 less fat cream cheese)
  • 1/4 cup coarsely ground coffee
  • 1/4 cup bourbon
  • 1/8 tsp xanthan gum


  1. Mix about 1/4 cup half-and-half with corn starch in a small bowl until fully dissolved.  Set aside.
  2. Put cream cheese in a larger bowl and set it aside to soften up.
  3. Put half-and-half, sugar, corn syrup, and salt in a saucepan.  Bring to a rolling boil and then allow to boil for 4 minutes.
  4. Turn off heat.  Add ground coffee.  Allow to steep for 5 minutes.
  5. Strain mixture to remove coffee grounds.  Return to (clean) pot and add cornstarch slurry while whisking.  Heat, whisking frequently, until it boils.  Mixture should thicken up.
  6. Pour mixture over cream cheese and whisk to combine.  Add bourbon and whisk again.
  7. Pour mixture into a ziploc freezer bag and cool in an ice bath.  (Or pour into any container and allow it to sit until it reaches room temperature if you're not worried about bacteria.)  Put in the refrigerator to sit overnight.
  8. Freeze in an ice cream maker.

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.

Sunday, June 16, 2013



I started this blog to discuss my efforts to make the kind of ice cream I like at home.  Here are the basics to get you up to speed:

  • I like fluffy, supermarket-style ice cream.  Ideally I like soft-serve, but since I don't expect to be able to make that I am aiming for regular ice cream that's as fluffy and soft as the stuff that used to come in half gallon rectangular containers from Sealtest or Hood (in Maine) when I was little.
  • I don't care about keeping it natural or organic at all.  If chemistry will give me good ice cream, I'm all for it.
  • I need to watch my cholesterol.  Because of this, I am trying to make ice cream using either low-fat dairy or non-dairy (soy, coconut) ingredients.  Fat free half-and-half works surprisingly well.  I'm also using non-egg thickeners like cornstarch and arrowroot because that removes egg yolks from the equation.
  • I use a KitchenAid mixer attachment with my mother's green mixer from 1970 to make my ice cream.

Vegan Chocolate Ice Cream: FAIL

I decided to try making a vegan soy-based ice cream.  I received "The Vegan Scoop" as a gift and this was my first try at using the ideas from it.  After reading about the trouble with soy-based ice cream flavors on Ice Cream Geek, I decided to try making an intense chocolate.  I've had good luck with chocolate in the past, even with Alice Medrich's very simple Sicilian Chocolate Gelato recipe, which was my first experience with cornstarch-thickened ice cream.

The chocolate recipe in The Vegan Scoop didn't look like it had enough chocolate in it to me, so I tried using the amounts from Jeni's "Darkest Chocolate Ice Cream in the World," as well as adding the coffee that she uses.  I followed The Vegan Scoop's suggestions, using a mix of soy milk and soy creamer, with arrowroot for thickening, and used a bit more sugar than I normally like to offset all the cocoa powder.

The arrowroot seemed to work very well.  I've never seen such a thick and smooth custard from dairy-based ice creams when using similar amounts of cornstarch.  There are warnings all over the Internet to avoid using arrowroot with dairy due to a "slimy" texture, but I may have to try it for myself some time.

Unfortunately, the finished product is pretty disappointing.  It's icy and dense, with a distinct soy milk flavor.  Not what I was after at all.  It's edible, but the texture is a real letdown.  I think next time I will try adding a small amount of xanthan gum.  Soy milk is known to have problems holding air bubbles and adding an emulsifier like xanthan gum should help.  In my dairy-based ice cream, the cream cheese takes care of this.

I'm still having trouble with the mixture not freezing as much as I think it should in the ice cream maker.  It doesn't seem to get much colder (or incorporate more air) after the first 10 minutes.  I'm thinking I should chill the mixture in the freezer a little before putting it into the ice cream maker next time, but I'm wary of getting it too cold since I had such a bad experience trying to follow the Cook's Illustrated advice of mixing in a portion of frozen ice cream base just before churning.  (The mix was so cold that the ice cream maker seized up in the first 5 minutes and nearly broke my ice cream maker.)  My freezer is at it's lowest setting and my refrigerator is 2 degrees celsius, as recommended by Ice Cream Science, so I think the temperatures should be working, but it is pretty warm in Brooklyn today.


As it turns out, my wife really likes this ice cream!  She prefers icier, less creamy ice cream.  She also likes how much chocolate flavor this has, which I agree with but I still taste the soy a lot.

Vegan Chocolate Ice Cream Recipe

NOTES: Here's my current recipe for future reference.  I do not recommend you make this without some tweaks like additional emulsifiers!


  • 2 cups soy creamer
  • 1 cup soy milk
  • 2 tbsps arrowroot powder
  • 1/2 cup cocoa powder
  • 1 1/2 oz dark chocolate (Green & Black is vegan, if you care about that)
  • 1/2 cup sugar
  • 1/3 cup corn syrup
  • 1/2 cup strong brewed coffee
  • 1/4 tsp salt


  1. Mix 1/4 soy milk with arrowroot in a small bowl.
  2. Put all other ingredients in a saucepan.  Heat, stirring often, until all chocolate is melted.  Bring to a boil, then remove from heat.
  3. Pour in arrowroot mixture while whisking.  Mixture should thicken quickly.
  4. Pour mixture into a container.  Let it sit until it reaches room temperature and then put it in the refrigerator overnight.
  5. Strain mixture through fine mesh strainer and then freeze in an ice cream maker.