What makes rye flour so great for starting a starter?

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.

4 thoughts on “What makes rye flour so great for starting a starter?”

  1. Back when I was first learning about sourdough I had an array of starters from different grains. Rye was certainly the safest bet. Then my enthusiasm waned, and I had all these active starters in the fridge that I was getting tired of feeding. I decided to keep the rye and the bread flour starters. When I got tired of feeding even those two, I froze them in small freezer bags. Now we can skip a long period of time, and then I suddenly decided I had to make sourdough loaves again.

    I was able to revive the bread flour starter without a hitch. (I still freeze bread flour starters in small zip lock bags.) The rye starter, however, wouldn’t budge. I had about 3-4 bags of rye starter from the same original batch, which was very active. Couldn’t revive any of them. Not sure if I messed up somewhere along the line or if rye starter just shouldn’t be frozen. Thoughts?

    1. That’s quite interesting. Could the rye starters been alive but just not rising much? That’s about the only thought I have. I haven’t kept a rye starter for quite a while, but when I did I remember that it rarely rose in the conventional sense, and was rather just pick-marked with holes, the result of popping gas bubbles.

      Dunno, Chana. That’s a puzzler!

      – JOe

  2. Don’t know why one would remain active and the other not but when I’ve got a good starter going I make some insurance by spreading a healthy spoonful on a silpat (I suppose parchment would work too but the weight of the silpat is helpful). I spread it as thin as I can and let it dry.

    When it’s completely dry you can flex the silpat to release it and store the resulting flakes and powder without needing to feed it.

    When you’re ready, add water to reconstitute it, feed it and carry on.

    Meanwhile, can it be that you’re back, Joe?!?!?!?!

    1. I was wondering when you might check back in, Rainey my good friend! 😉

      Yes, I’m back and posting, though not with the same frequency. But it feels pretty good I have to say!

      And BTW that’s good advice!

      – Joe

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