Yeast Water questions.
It's snowing like crazy outside, which tends to decrease traffic through the ER, so I'm sitting here thinking about my next baking experiment (as I often do when it gets cold outside).
I keep seeing post after post about the vigor of raisin yeast water as a leaven, and I am inspired to give it a try. Several posters have written of yeast water procedures; Akiko (who posted under the name of Teketeke) gave an especially detailed description in one of her posts. But I've not yet been able to find a "yeast water primer" as it were, so I thought I'd just throw out a couple questions to those among you who have been using it successfully.
My sourdough culture has been happily living in the back of the fridge for over a decade, emerging when it calls to me, then retreating to its blissful dormancy every few weeks. But in Akiko's post she mentions that she only keeps a raisin yeast water going for about six months then she tosses it and starts over. Why is that? Does it go bad? Lose potency? Change flavor?
And during that six months, how often is it recommended that you refresh it with more raisins? I can let my sourdough go up to four months and still revive it, but I'm suspecting that the yeast water would die much sooner with no more of a substrate than water and a little fructose.
At my local health food store I can buy granulated fructose right off the shelf - could I refresh with that, or would a fresh batch of raisins be a better choice? They also sell organic raisins, so either way is fine - I was just curious.
In one of the articles I found on Google regarding yeast water, it was mentioned that the yeast that lives on raisins tends to be particularly vigorous. However, Dabrownman, in a recipe he called Teketeke bread (to honor Akiko) used a yeast water made from apples and mandarin oranges. Does the fruit you choose have a significant impact on taste, and therefore lead you to different choices? Or is it a matter of the specific strains of yeast that you are trying to isolate from different kinds of fruit?
Also, with regard to fruit yeasts, I read an article many years ago about starting a sourdough culture by submerging fresh grapes in a flour/water slurry until it begins to produce bubbles. Has anybody tried using fresh grapes rather than raisins to make a yeast water? In that article, it said that the grayish "frost" on the surface of a grape skin is the presence of the yeast. It makes sense that the yeast on fruit would be present on the outer surface of the skin, so if you're using other fruits do you need to include their skins/peels as well? What about sugary vegetables or legumes (like peas or corn) as a possible component?