Yeast sugar and fermentation, OH MY!

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flybeau

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I have a one gal brew kit, hydrometer, some yeasts and plenty of questions mulling through my mind. This is the weekend that I'm going to start my very first craft cider. :tank:

I have come across some conflicting information regarding the relationship between yeast and sugar & alcohol. If anyone has advice or a resource (online or digital preferable) that would help, I would be grateful for that information. Here's my confusion.

It was first explained that yeast has a tolerance level for alcohol and would die out when reached. Beer yeasts 4 to 6 percent, ales slightly more and wine yeasts in the 20% range. But I'm also told, seemingly in the same breath, that if there is sugar fermentation will continue unless stopped. Now on this board there are a lot of discussions stemming off this subject. From bottle carb'ing to cold crashing and heat pasteurizing to drying out the cider in the bottle if fermentation is not stopped, which would seem to contradict the alcohol tolerance theory. If the tolerance theory is true then would one not add enough sugar for the yeast to reach it's alcohol content and have enough sugar left over for the desired sweetness? And if you Bottle it at the right time there would be enough process to carbonate the bottle? If you wanted a carbonated drink.

Thanks
Beau
Please excuse this newb, for he is a newb.
 
Fermentation will stop eventually, regardless of the yeast. It's the reason we can't brew liquor. It has to be distilled (concentrated) to hit such high levels. Wine yeasts typically go higher, and many ferment out drier.

You can brew a batch of beer, ferment it out as far as it will go, then add corn sugar and it will fire back up. Belgian styles do this sometimes. You have to be careful though because fermenting pure dextrose doesn't taste like fermenting wort. It can lead to desirable flavors if done properly, but it needs to be the right style.

I guess theoretically you could brew a batch, then add your priming sugar up front. However you'd have to be able to check your gravity often, as it could easily ferment up the sugar you added. Actually it could possibly ferment the pure sugar up front, and then proceed to the other saccharides leaving you with beer that tastes like you fermented sugar in it.

The real answer is that it's just easier to brew the beer, let it finish out, then add sugar as you bottle. That way you can't F it up.

Simplicity is key, especially if you ever have any hopes of duplicating a great brew.
 
Thank you strat. You are right I need to keep it simple. I tend to get caught up in figuring out how something works. Why is it done the way it's done? Teachers "loved" me lol.
 
It was first explained that yeast has a tolerance level for alcohol and would die out when reached. Beer yeasts 4 to 6 percent, ales slightly more and wine yeasts in the 20% range.

Thanks
Beau
Please excuse this newb, for he is a newb.


That is 100% false. I hope that helps.

Although, particular styles, like a Lager, the yeast may "die out" early, but it's due to the fermentation technique, not the alcohol content.

You'll see grades of yeast online, stated an alcohol tolerance, but that's a very loose approximation, it's more of a style guideline. Although a yeast rated at 12% may very well be able to go to 18%, it isn't desirable because it would take a good amount of work to get it that high, and it will create many off flavors and aromas, whereas you could just start with a more appropriate strain for the style.
 
the 2nd piece of the puzzle is that if you add so much sugar that you exceed the alcohol tolerance of the yeast -- you typically produce a sweet wine that tastes like gasoline -- with all sorts of "Hot" tasting fusel alcohols and other components that taste off/strange.... Aging for a long time (sometimes years) is really the only way to "Fix" this....

That is why we ferment well below the alcohol tolerance, then use other techniques to stop fermentation if we want it sweet....

Thanks
 
Similarly, or conversely, alot of the old timers go crazy with the sugar so it's so sweet that you don't even notice the 'hot' alcohol, and they drink it pretty young. "Sweet Funky Blackberry Water that makes you dizzy".... a la` Foxfire.
 
Fletch I've been pondering what a strait blackberry brew would turn out to be. Would it retain that tart flavor. I will at some point try it I'm sure, I love blackberries.

This makes sense. The flavor profile will change as the yeast consumes the sugars. A friend is making wine and gave me a sample of strawberry banana wine that had a overwhelming alcohol bite to its aroma. But by the 3rd sip the flavor started to come out and was easier to drink. He let it ferment until it stopped with a few rack offs. I think this is what you are describing in letting the yeast go to alcohol tolerance because this was still very sweet and strong and he did not back sweeten.

So fermentation can be stopped with heat and cold. Can it be filtered out?
 
You gotta try to decipher in your mind what the fruit would taste like without any of the sugar....

In the case of Blackberry and Raspberry juice... Tart is a huge understatement.... Think battery acid!

Fresh/raw, they are massively acidy with a lot of sugar to give them that sweet/tart flavor.... Take away all the sweet and you are left with crazy bitter/sour....

Then, they have a massive intensity to the flavor..... and that becomes so intense that you loose the essence of blackberry -- you just end up with a big glass of pure Bitter acid + alcohol! Trust me on this......

Look at the typical Black berry wine recipes -- you see a lot of water and sugar for a relatively small amount of berries.... This isn't a mistake.

For your 1st batch -- try to follow an established recipe.... See how it comes out and how it ages..... Then, experiment with fine tuning it.

Thanks
 
That is 100% false. I hope that helps.

Although, particular styles, like a Lager, the yeast may "die out" early, but it's due to the fermentation technique, not the alcohol content.

You'll see grades of yeast online, stated an alcohol tolerance, but that's a very loose approximation, it's more of a style guideline. Although a yeast rated at 12% may very well be able to go to 18%, it isn't desirable because it would take a good amount of work to get it that high, and it will create many off flavors and aromas, whereas you could just start with a more appropriate strain for the style.

And that's unfortunately about 95% false, yes the alcohol tolerance is a range, but it's no where near a 6% difference. Generally it's 2-3% diff.

Nottingham, a yeast rated at 10-12% alc tolerance will never get to 18% no matter how much coaxing you do.

to the OP, the two statements really aren't in contradiction, in the presence of sugar yeast will ferment up to its range of alcohol tolerance.

The practice is fairly common in some styles, like sack meads.

The reason it's not that widely used is that the high alcohol content takes months to mellow and since the tolerance is a range, it's hard to get a consistent flavor.

The 2-3% difference in tolerance is also the reason you can't use it for bottle priming, even that small a variance can lead to way to much pressure causing bottle bombs.
 
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