What Are These Strange New Products Used in GF Foods?

New Products Used in GF Cooking

I recently got Silvana Nardone's "Cooking for Isaiah-- Gluten-Free and Dairy-Free Recipes for Easy, Delicious Meals."

Apple Cider Vinegar: I saw this ingredient in many of Nardone's recipes and asked myself, "How can I find that? Will it come in kosher?" The answer is easily! I'm not sure how readily available it is in Israel, but when I stopped by the local Hannaford today, there were several versions. The one that I chose is from "Bragg"-it boasts a variety of certification. It is USDA-Organic, Gluten-Free, has no preservatives, and has a KSA certification.

Kosher: KSA is an abbreviation for Kosher Certification of America. It is a run by a Chabad-Lubavitch rabbi, and while the Lubavitch group can be controversial, apple cider vinegar is a fairly basic product. Here is KSA's info: http://www.ksakosher.com/

Xanthan Gum: I had seen this name before on the ingredients list in many, and do be honest, it seemed like a freaky name/chemical. Well, it turns out not to be as creepy as it sounds-- you can get it in Israel apparently (kosher!) and from Bob's Red Mill. I bought some today at a Hannaford store (for $10.00 for the kosher version

Kashrut: Rabbi Avrohon Teichman of http://mykosherla.com/kehilla-kosher/ of Los Angeles, CA.

Now, TWO KEY questions:

1) Does anyone know where to find kosher chestnut flour?
2) Does anyone have any good, TESTED, for oat-flour challah? I need something to make motzi on! I found several recipes when I googled "oat flour challah" on ImaMother (a frummy site for frummy mother's)