Why do I keep two starters
I've always kept two starters - one wheat, one rye. Well I say always, I've only actually been using sourdough for a few months. At first, I kept them at 100% hydration and stored in the fridge. I bake roughly every 4-5 days, and alternate rye and wheat bakes so each starter is only used every 8-10 days or so. At the beginning, I wasn't discarding any of it, I'd just refresh, then store about 1/3- 1/4 and use the rest in the bake. However, I was suspecting that my starters weren't totally happy that way as I'd often have to use more starter than a recipe calls for, although I must say my kitchen is quite cold (rarely above 20 C).
After I went on holiday for two weeks, I took them out of the fridge and maintained at room temperature for a while. I worked out that in my cold kitchen, I could get away with refreshing them every 16 hours rather than the "standard" twelve (or even 18, at a push). However, I now had to discard a lot (which I stored for use in pancakes as I hate waste). More recently, I decided to lower their hydration to around 80%, this way I can only feed them once a day. Still, there's more discarded starter accumulating and I just don't get the time to bake all those pancakes! Especially as my favourite pancakes are white flour, kefir based, rather than whole flour sourdough based.
That said, I do like the convenience of not having to wait a day for my starter to warm up and get up to speed, and the comfort of knowing that it's probably healthier at room temp than in the fridge.
My question is then, do rye and wheat behave differently enough to warrant two starters? Or shall I just keep one to minimise waste?