Active kefir is my choice, but you can use dehydrated or frozen grains for a starter if you don't mind waiting a few days to get going. It doesn't take much and it doesn't take long to get a fermentation going if using active. Very recently I used a single tablespoon kefir whey in the bottom of a gal jar shredded red cabbage kraut mix and it was bubbling nicely before 18 hours had passed. Here is a link that might be useful: Probably more abt kefir than you possibly ever wanted to know

That is good to know. My experiences with yogurts give a questionable outcome so far. Perhaps using the commercial starter would be more consistent. I do keep bread sour dough starters also. So far have never had to resort to using the dried specimen that I have way back in my fridge - just in case my usual wet starter becomes a casualty. I noted at the King Arthur website that you suggested - that they also have pound cake mix. Yesterday, was my first attempt at pound cake - which I made with sour cream -got the recipe on the "net" somewhere. It was good, but I noted a bit too sweet for my taste buds - especially because we have been cutting down a lot on sugared things. It was interesting to see that all of the recipes that I searched used 3 cups of sugar. Wow - that seems like a lot, but perhaps pound cake can't be made any other way. It was of interest to me - that I used some of my frozen eggs from last year's cache, using 2 frozen cubes per 1 egg - and adding to the mixer alternately with flour each time. Was not sure how it would be, but outside of the sweetness, it was great. Thanks for your comment - always so appreciated. By the way, did you manage to get enough from your garden after all the rain you had. I'm now in the process of "doing" prep work for beds - compost, fertilizer, clean up and have some early veggies under lights already for October planting when weather cools a bit. Old age slowing me down some - and wish I had much more compost ready, but that's the breaks. Bejay

Linnea, the banana bread recipe I use calls for 1/2 cup of sour cream, so that's what I always use. Obviously, Greek yogurt has less liquid since the liquid (whey) is drained out of it. For baking purposes, your question regarding adding milk made sense. See if this (from Cook's Illustrated) might help when it comes to baking with yogurt... "We weren’t surprised with our findings when we baked batches of bran muffins and peach cobbler (with a biscuit topping) using these two different types of yogurt. In both instances, the samples made with Greek yogurt tasted slightly drier than those made with American yogurt. To come up with a formula to compensate for the difference in moisture content, we drained 1 cup each of plain whole-milk, low-fat, and fat-free yogurt in a fine-mesh strainer lined with cheesecloth; after two hours, 1/3 cup of liquid had been exuded from each sample. Armed with these results, we went back into the test kitchen, reducing the amount of Greek yogurt used in our recipes by one-third and making up the difference with water. The results? Tasters found the muffins and cobblers nearly identical. So to substitute Greek-style yogurt for American-style yogurt in baked goods, remember this rule: Use only two-thirds of the amount of Greek yogurt called for in the recipe and make up the difference with water."

If the sauce is used to cook the chicken in, then I would have no concerns about freezing the leftovers. I make various recipes that include a dairy based sauce of some variety - yogurt, sour cream, even heavy cream - and after cooking, the leftovers freeze perfectly well. Uncooked dairy may not freeze well (although I have no issues with cheeses or butter) but dairy used as a component of a cooked sauce freezes just fine. I find no deterioration of texture, splitting or separating or loss of flavor.