Bakers will forever remember 2020. Not as The Year of The Pandemic, not as The Year of Social Unrest, but as the beginning of The Golden Age of Sourdough. These days just about everyone has a bread starter in their house, or they’re looking to start one. Reader Glen is in the latter camp, and has been doing research on the best way to get a starter going. He’s seen more than a few posts that recommend rye flour as a starting point. What he wants to know is: what makes rye four so special when it comes to starting starters?
The answer is that rye flour has more wild yeast in it than other types of flour. Here it might be useful to back up a bit and take note of the fact that rye is not actually wheat, but rather its close cousin, and an odd one at that. So odd in fact that rye wasn’t widely cultivated until about 400 A.D., which is many thousands of years after wheat was first domesticated. The reason (probably) was because rye doesn’t make especially good bread.
Rye has other virtues, however. It grows well in poor soil. It has big thick roots which help it resist drought. It can withstand temperatures that would kill most other cereal grains. It’ll even remain alive when it’s covered with snow. That’s a handy thing, and indeed many North American farmers like to plant rye in the fall after other crops have been harvested, because a covering of rye helps prevent soil erosion and compaction in the off-season.
So you can see why rye has always made a handy “Plan B” crop for farmers. It may not make an especially good loaf, but you can grow it on bad, nutrient-poor land, and odds are it’ll still be there in the bad years when the more toothsome wheat harvests have failed.
That said, rye behaves rather strangely, as I mentioned. Its berries will often germinate while they’re still on the ear. And because those germinated berries are still on the ear at harvest time, they end up being collected along with all the other un-germinated rye berries and milled into flour.
What difference does that make? Well as you may recall from previous discussions about germination, it’s a process whereby a grain berry sends out a shoot. The outer shell (bran layer) cracks open so the shoot can emerge. At the same time enzymes in the berry activate and begin the process of breaking down the long-chain starches (stored in the endosperm) into the simple sugars the shoot needs for fuel. But that also presents a big opportunity for invading yeasts, molds and bacteria. Once the berry opens, the buffet starts. Critters enter, and start their own eating and reproduction process.
So while rye flour may look like a conventional flour, it really isn’t. It’s actually a riot of starch, sugars, enzymes, yeasts and bacteria. No wonder it makes a starter so readily — you just add water, so to speak. Once the culture is growing you can just switch to another type of flour and continue on from there. Not a bad plan, actually.