Yeast Starter w/ Sugar

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PT Ray

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Does anyone have experience making a yeast starter with table sugar and yeast nutrients?

One of the conerns is if the yeast nutrients breakdown with heat, prevention me from boiling the starter before adding yeast. I figure there has to be an issue being overlooked otherwise it would be the thing to do.
 
I think yeast will stop producing the enzyme required to consume complex sugars like maltose if they get fed sucrose, or something like that. I am not a chemist or biologist.
 
You'll always want to boil your starter wort, regardless. I usually boil my starter wort and then add the nutrients once it has cooled down. I wouldn't really recommend using pure sugar though. Just pick up a package of DME and use that instead.
 
I think yeast will stop producing the enzyme required to consume complex sugars like maltose if they get fed sucrose, or something like that. I am not a chemist or biologist.

That's what the cognoscenti claim. You actually kind of want the wort for your starter to be somewhat similar to the wort to be fermented. Even with yeast nutrient, I'm not sure that the starter liquid with just sugar would be nutritionally/chemically complete enough to ensure good yeast health. The goal of a starter is first-most to have a healthy, active yeast culture for the beer. The actual number of yeast is a close second. Pitching a crap load of unhealthy, mutant yeast is obviously not a good thing, better to under-pitch healthy yeast.
 
Pitching a crap load of unhealthy, mutant yeast is obviously not a good thing....

I thought mutations were randomly derived, unless we are talking exposure to radiation or something. Are you saying that sucrose is a mutagen?

Those of you who are interested in the answer to the OP question, keep an eye on this thread. A guy named slouch made a couple posts talking about his method for propagating yeast: making homemade nutrient by boiling the trub from a secondary fermenter and then using it in conjunction with plain sugar in order to make a starter. I suspect the guy knows what he is doing from the looks of his post, so I tend to doubt that he is making under-attenuated mutant beer. But it would be nice for him to revive the thread and elaborate a bit.
 
I know this thread is from three years ago, but sugar is not a mutagen. However, yeast (like all bacteria) go through generations far quicker than humans, so their evolution is accelerated. Many breweries won't reuse there yeast for more than 10 batches because it changes into something that they didn't design.

The reason yeast will mutate when using sugar for a starter is because there is no evolutionary pressure for them to consume complex sugars like Maltose, since sucrose is so abundant. It will still work but the ferment will probably be slower.

Also, sugar has none of the nutrients that yeast needs, so if you really must use sugar as a starter add a yeast nutrient.

Cheers
 
I know this thread is from three years ago, but sugar is not a mutagen. However, yeast (like all bacteria) go through generations far quicker than humans, so their evolution is accelerated. Many breweries won't reuse there yeast for more than 10 batches because it changes into something that they didn't design.

The reason yeast will mutate when using sugar for a starter is because there is no evolutionary pressure for them to consume complex sugars like Maltose, since sucrose is so abundant. It will still work but the ferment will probably be slower.

Also, sugar has none of the nutrients that yeast needs, so if you really must use sugar as a starter add a yeast nutrient.

Cheers


Just FYI, it has nothing to do with mutations or evolutionary pressure. You'd have to go thousands of generations of disuse to start selecting for a strain of yeast without a maltase gene (which produces the protein for breaking down maltose: maltase). All brewer's yeast have the genes to produce enzymes that break down sucrose and maltose. If you grow yeast in sucrose only, it's a waste of energy for them to make maltase, because there's no maltose, so they shut down that pathway, stop making that enzyme.

If you then toss them in a maltose-rich enviroment, they set to work on the sucrose and other simple sugars available to them. When that runs out, they have to spend even more energy switching maltase pathway back on, if they can do it at all, because by that time, the pH of the wort has dropped, easily utilized sugar is scarce, and alcohol content is rising.
 
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