yeast and gravity/alcohol tolerance

[wolfej50]

Are there any published charts or guidelines that document the gravity or alcohol tolerance of the various available yeasts? I just faced a situation in which my actual OG was much higher than expected and the yeast I had purchased was probably not up to the task of fully fermenting all of the sugars. I'd like to buy one or two high-gravity yeasts to have just in case this happens again.

 

[acidrain]

If you are getting much higher OG's, then you should add water to thin it out to style. Otherwise your bitter to malt ratio will be off.
I suggest that maybe your calculated boil-off rate is much higher than you think.
Dial in your system and hit your numbers. That is the key to repeatable results.

 

[TastyAdventure]

What was your OG? Most yeasts can handle more than you'd think

 

[TastyAdventure]

What was your OG? Most yeasts can handle more than you'd think

 

[wolfej50]

In my last batch, my measured OG was 1.080. However, I don't think I had a good mix of my top-off water (after boil volume was 4 gal and topped off to 5 gal). Also, there was a good bit of solid matter in the sample that may have thrown off the sample. I used Windsor yeast, which I understand has low-mid attenuation. Should have thought of adding more water (duh!). My FG was 1.024. My primary hypothesis is that the yeast reached its tolerance for alcohol. I'm bottle conditioning. I know there is a chance that fermentation hadn't yet finished. I'm going to sample a bottle after 1 week and check for pressure. If the bottle is flat (as I suspect) I'll accept the fact that I may have flat beer. If the pressure is significant, then I'll probably have to dump or rebottle. I'm taking notes as I improve my techniques, so, hopefully, I'll be able to improve on hitting my targets going forward. In the meantime, I'd like to have some tricks up my sleeve (like high gravity yeast) for when things don't go as expected.

 

[flars]

The yeast manufacturers will have the details you want for all of their yeasts on their web sites.
Your FG could have been high due to a high mash temperature creating unfermentable sugars, or a high percentage of unfermentables in the recipe.

 

[wolfej50]

Mash temps were on target, so that wasn't it. I did look at the spec sheet for Windsor yeast and it did say that FG could be higher than normal. How much higher is another question. My thinking is that, all other factors being the same, if there are digestable sugars available, any yeast would eat all that is available. So, the only reason a yeast would leave sugars undigested would be if some other factor, e.g., alcohol level, changed. We'll see when I open a sample bottle. Flat beer would support my hypothesis and significant pressure would refute. I love science.

 

[wolfej50]

I opened a test bottle last night, five days after initial bottling. The pressure seemed about right, not flat and not on the verge of blowing up the bottle. There was a good bit of foaming, though. If bottle fermenting is like in the fermentation bucket, i.e., most active in the first few days then tapering off, then I think I'm good. I may have some acetyle (sp?) that will hopefully go way over time.

 

[Calder]

In beer wort you have a lot of different sugars, ranging from simple sugars to very complex sugars. All yeasts can convert the simple sugars, but each yeast has a different level to which it can convert the more complex sugars.

A low attenuating yeast like Windsor is not very good at converting complex sugars, and will leave almost any beer with a relatively high gravity. A high attenuating yeast such as 3711, will eat almost anything, taking most beers down to close to 1.000.

At 1.080 (or whatever your gravity was - it was not really clear), you have not exceeded the alcohol tolerance of Windsor. Windsor will happily work on the simple priming sugar you have added. There will not be any issue with priming.

 

[wolfej50]

Thanks Calder. I wasn't aware that high attenuation meant that those yeasts could actually metabolize the more complex sugars (vs. higher alcohol lever or more aggressive metabolizing of the simple sugars). I love it when I learn something new.