non-visible infection when re-using yeast for cider??

I had been re-pitching unwashed S-04/nottingham yeast for my apfelwein-style ciders (technically, just dumping in more juice and sugar, having pasteurized the sugar+nutrient mix and used starSan on the outside of the juice containers, and the equipment.)

Two times out of 8 so far, I have had aroma indications of infection: once butyric acid (vomit) likely from Clostridium, and once major diacetyl (buttery) possibly from Pedio. Both were confirmed with a side-by-side tasting of a beer judge training chemical extract kit.

My theory is that since there is no hops to prevent infections, only alcohol, that an infection is setting in, or growing enough to notice, at some point in the second or third pitch. Whereas with repitching for beer, there is the anti-microbial hop acids making infections much less likely to take hold. I have dumped those two batches and yeasts.

Has anyone else experienced this, or has anyone had a large history of reusing cider yeast without issue?

I've been using small cider batches as my starter for beer brews without issue. refrigerate then decant .5 or .75 G cider into swingtop bottles (for later enjoyment), dump most of the remaining slurry into my beer that is ready to go and then top off the cider starter with fresh apple juice and referment. This has been working like a charm for 3 or 4 generations with no vomit smell. What sort of fermentation vessel are you using? Vomit smell I believe is indicative of both infection and oxidation I believe.

MrFancyPlants said:

I've been using small cider batches as my starter for beer brews without issue. refrigerate then decant .5 or .75 G cider into swingtop bottles (for later enjoyment), dump most of the remaining slurry into my beer that is ready to go and then top off the cider starter with fresh apple juice and referment. This has been working like a charm for 3 or 4 generations with no vomit smell. What sort of fermentation vessel are you using? Vomit smell I believe is indicative of both infection and oxidation I believe.

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I use 5 gallon better bottles (they technically hold about 5.5 up to the top) and standard S-airlocks with vodka. The 'good' batches have been just fine, even those that were done with reused yeast.
I'm considering just using a fresh yeast for every cider batch.

andrewmaixner said:

I'm considering just using a fresh yeast for every cider batch.

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I would S04 and Notty are around $1.50ea. Its worth it when you have a 25% (according to you) chance to lose $25-$50 on a single batch.

I think I would only reuse yeast if I was using wild yeast and found an awesome one. But I haven't experimented with that yet.

DaMonkey said:

I would S04 and Notty are around $1.50ea. Its worth it when you have a 25% (according to you) chance to lose $25-$50 on a single batch.

I think I would only reuse yeast if I was using wild yeast and found an awesome one. But I haven't experimented with that yet.

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my LHBS has them around $4. Wine yeasts though are $1, and I'm planning to try one of those for the next batch.

My "loss" on a batch is more-so important in terms of time. The ingredient cost is only about $17 +yeast, so it's on the very low side of that estimate. Store juice, nutrient, sugar, molasses, and yeast.
I've thought about trying one of the fancy cider concentrate kits, or real apples, but when the people I make it for love what I'm already doing, I figure why bother? I drink the beer, they they drink the cider