Can I sulfite before priming and bottle-conditioning?

[piojo]

I'd like to have the best of both worlds regarding easy carbonation, and shelf life (reduced oxygen). If I add enough sulfites to bind with oxygen, will that prevent yeast from bottle conditioning?

If I can do this, would I need to add fresh yeast?

 

[RPh_Guy]

Yes you can sulfite.
No you don't need fresh yeast.

I'd suggest keeping molecular SO2 around 0.5-0.7ppm, based on pH

http://fermcalc.com/FermCalcJS.html

Cheers

 

[Hermit]

You're solving a problem that doesn't seem to be a problem for most people. If you bottle carb then the yeast in the bottle are your little friends when it comes to any residual molecular O2. That small space at the top of the bottle is only about 21% O2 to start with.

 

[JimRausch]

If you want to add the Camden, do it at least 24 hours before bottling in order to let the SO2 to degas. Otherwise you might get some off-flavor/odor.

 

[RPh_Guy]

Hmm is this about beer?
I assumed you weren't asking about beer, but my advice still mostly applies.
For beer, add around 20-30ppm free SO2.
We can safely ignore molecular SO2.

Why aren't sulfites used in beer? Because beer typically isn't exposed to much oxygen and beer is generally consumed before oxidation becomes a problem.

your little friends when it comes to any residual molecular O2

Yeast do not consume all the oxygen in the bottle. There is plenty of oxygen left over to oxidize.

do it at least 24 hours before bottling in order to let the SO2 to degas.

At the correct dosage, you do not want the SO2 to off-gas. That's the whole point of adding it -- in needs to be in the bottle to prevent oxidation.
There should not be any off-flavor at 20-30ppm.

Cheers

 

[piojo]

Hmm is this about beer?
I assumed you weren't asking about beer, but my advice still mostly applies...

Why aren't sulfites used in beer? Because beer typically isn't exposed to much oxygen and beer is generally consumed before oxidation becomes a problem.

Thanks! You're right, it's a mead. It's a hopped mead, so it's the worst if both worlds: longer fermentation with lots of head space, and hops. And it's an intense flavor, so it won't get drunk that quickly, unlike the people that consume it.

 

[RPh_Guy]

Lol, good luck!

I once had a sparkling hopped (Cascade) session blackberry melomel. It was very tasty.

 

[Hermit]

Yeast do not consume all the oxygen in the bottle. There is plenty of oxygen left over to oxidize.
Cheers

You care to put a quantity on that "plenty" remark? From Chris White's book on yeast:

"The uptake of oxygen happens rapidly, with the yeast usually depleting wort oxygen levels within 30
minutes of inoculation." page 27

While he doesn't give the level of oxygenation, he seems to think it should be 12ppm so may have been using that in his tests. We're talking the small amount in the head space of a properly filled bottle and practically none in the bottled beverage. Because of where this was posted I was ass u me ing beer since it wasn't stated at the onset. Since oxygenation has never been a problem for me when bottle carbing I think you need to explain this "plenty of oxygen left over to oxidize" because frankly it flies in the face of a long used practice. If the yeast are active enough to carbonate they should be scarfing up the oxygen.

 

[piojo]

You care to put a quantity on that "plenty" remark? From Chris White's book on yeast:

"The uptake of oxygen happens rapidly, with the yeast usually depleting wort oxygen levels within 30
minutes of inoculation." page 27

While he doesn't give the level of oxygenation, he seems to think it should be 12ppm so may have been using that in his tests. We're talking the small amount in the head space of a properly filled bottle and practically none in the bottled beverage. Because of where this was posted I was ass u me ing beer since it wasn't stated at the onset. Since oxygenation has never been a problem for me when bottle carbing I think you need to explain this "plenty of oxygen left over to oxidize" because frankly it flies in the face of a long used practice. If the yeast are active enough to carbonate they should be scarfing up the oxygen.

You made many assumptions and I don't think you realize it. First, yeast in a finished fermentation is not vigorous like yeast pitched into a new must. Next, everything happens more slowly with mead than with beer.

And let's compare the amount of fermentation that happens in primary versus in the bottle: in a 10% ABV fermentation, a liter of must converts around 180 g of sugar to 90 g of alcohol and 90 g (45 volumes!) of CO2. I'm the bottle, I'm going for 2-5% of that. And let's say the yeast utilizes 12 ppm of oxygen four times. 48 ppm if oxygen in a 330 mL bottle is 16 mg of oxygen (actually 0.32 mg according to the 2% conversion factor). This is the oxygen present in 1.8 mL of air. Yeast will use up the oxygen in a full bottle, but not a bottle with headspace.

Note: I was a little sloppy with the math, using ABV as a proxy for the amount of total fermentation instead of using sugars. I won't correct it because this is an inherently sloppy type of logic: we can't actually know whether yeast use oxygen in the bottle as they do after pitch. It's best not to get a false sense of security with more careful numbers.

 

[Hermit]

You made many assumptions and I don't think you realize it. First, yeast in a finished fermentation is not vigorous like yeast pitched into a new must. Next, everything happens more slowly with mead than with beer.

And let's compare the amount of fermentation that happens in primary versus in the bottle: in a 10% ABV fermentation, a liter of must converts around 180 g of sugar to 90 g of alcohol and 90 g (45 volumes!) of CO2. I'm the bottle, I'm going for 2-5% of that. And let's say the yeast utilizes 12 ppm of oxygen four times. 48 ppm if oxygen in a 330 mL bottle is 16 mg of oxygen (actually 0.32 mg according to the 2% conversion factor). This is the oxygen present in 1.8 mL of air. Yeast will use up the oxygen in a full bottle, but not a bottle with headspace.

Note: I was a little sloppy with the math, using ABV as a proxy for the amount of total fermentation instead of using sugars. I won't correct it because this is an inherently sloppy type of logic: we can't actually know whether yeast use oxygen in the bottle as they do after pitch. It's best not to get a false sense of security with more careful numbers.

The basic premise is that yeast will use oxygen in the head space and hasn't ruined hundreds of thousands of batches in the past. The yeast that Cris talks about take up the oxygen well before just about ANY alcoholic fermentation has started so I don't see your point of trying to tie the two together. The point is that the yeast are oxygen scavengers. If you have measured numbers and not assumptions of your own to show that oxygenation is a problem, then present those. You are making assumptions of your own. I know a mead maker that has won national awards that broke out a bottle of 13 year old mead at a Christmas party and it wasn't oxidized. Do all the back of the envelope calculations based on your assumptions you want. I've tasted proof that bottle aged meads aren't going bad from the "plenty" of oxygen in the head space.

 

[RPh_Guy]

It's well-known that yeast remove some oxygen, but clearly not all of it.

As piojo said, you can't extrapolate what happens in fresh wort to what happens in bottled beer headspace.
Hop aroma is much more affected by oxidation than a traditional mead, so that's not a useful comparison either. Wine and mead also typically contain sulfites, which prevent oxidation.

Bottled-carbonated beer is not impervious to oxidation. Just ask any BJCP judge.
Here's an example, and some info about the amount of O2 in headspace: https://aussiehomebrewer.com/threads/how-much-o2-does-the-yeast-actually-consume-in-bottle.94479/

Anecdotes may not really be useful to answer this question because some people don't recognize oxidation, don't mind oxidation, and may even prefer it.
https://www.morebeer.com/articles/oxidation_in_beer

This is the most scientific evidence I can find:
https://www.homebrewtalk.com/forum/...dspace-o2-in-a-bottle-conditioned-ipa.653784/
Since CO2 purging reduces oxidation, it's easy to conclude that yeast don't consume all the oxygen in the headspace.

One thing I do wonder is whether vigorously shaking the bottles immediately after capping to dissolve the headspace O2 would help the yeast utilize more of it.

 

[piojo]

Do all the back of the envelope calculations based on your assumptions you want. I've tasted proof that bottle aged meads aren't going bad from the "plenty" of oxygen in the head space.

Okay, that's actually a much easier question. I made a bottle-conditioned plum mead I liked very much. I misplaced a bottle and opened it after six months. It was no longer enjoyable to drink. It was pasteurized (and did not seem infected), so I suspect oxidation. This is stronger proof than my calculations, though the calculations are ridiculously optimistic as far as what the yeast could do, as I did not add any "penalty" factor for yeast being old and in a high-alcohol medium.

@RPh_Guy Thanks for the links, I'll read those later. I've read that slight oxidation is desirable in wines as well, but the amount is tiny.

 

[Hermit]

Okay, that's actually a much easier question. I made a bottle-conditioned plum mead I liked very much. I misplaced a bottle and opened it after six months. It was no longer enjoyable to drink. It was pasteurized (and did not seem infected), so I suspect oxidation. This is stronger proof than my calculations, though the calculations are ridiculously optimistic as far as what the yeast could do, as I did not add any "penalty" factor for yeast being old and in a high-alcohol medium.

@RPh_Guy Thanks for the links, I'll read those later. I've read that slight oxidation is desirable in wines as well, but the amount is tiny.

So now your suspicions are stronger than your calculations? Again, I've had mead that was over 10 years old that wasn't oxidized. I don't know why I bother brewing. All of my beverages will be ruined by oxidation if I don't drink them quickly. I'm out. I have to leave before my basement full of brew goes bad just because you guys say so. Bye.

 

[RPh_Guy]

Maybe the truth lies in a middle ground between bottle conditioned beer never oxidizing, and all beer going bad immediately?

 

[JimRausch]

Those are great articles RPh- thank you. I especially got a lot out of the George Fix paper, although admittedly I had to read through it twice in order to digest it. The Takuro thread from HBT makes me want to look for a can of the Wine preserver he talks about.
I would really love to see an experiment where someone measures the headspace O2 and dissolved O2 in a freshly bottled beer and then serially down the road. Would also be nice if they(the infamous 'they') could measure amounts of known staling compounds. Sounds like a doctoral thesis for someone. In the meantime, we all just do what we can do.

 

[Hermit]

https://www.homebrewtalk.com/forum/threads/yeast-and-oxygen.642044/#post-8175427

I'll take AJ's research over any of this.

From MBAA's 'Beer Packaging, 2nd Edition

"Generally, a 12-oz. (355-mL) bottle
of beer containing less than 0.5 mL of headspace air has
adequate shelf life for most local distribution scenarios.
Bottle conditioning or retaining a small amount of
yeast in the beer can help reduce oxygen content quickly
and extend shelf life. Also available are crowns with
oxygen-scavenging liners, which absorb oxygen in the
beer headspace, and oxygen barrier crown liners, which
can help keep oxygen from entering the crowned package.
Brewers should be aware that some of these liners “scalp”
or absorb hop aroma compounds."


Remember, my original post said yeast helped with the O2 situation. Even on of your earlier quoted threads listed a pointer to another thread asking why this was being rehashed as it was already a 'solved' issue. OK. Now I'm out for another 6 months to a year. Not that I expect this place to get any better in the mean time.

 

[RPh_Guy]

I'll take AJ's research over any of this.

From MBAA's 'Beer Packaging, 2nd Edition

"Generally, a 12-oz. (355-mL) bottle
of beer containing less than 0.5 mL of headspace air has
adequate shelf life for most local distribution scenarios.

All drama aside...

Don't forget to read AJ's next post on that thread.
Less than 0.5mL of head space is much smaller than what almost every homebrewer leaves, so this really doesn't apply to us.

The phrase "adequate shelf life" acknowledges that there is still indeed a shelf life, presumably limited by the effects of oxidation.

We all agree the yeast help remove some oxygen. However there's still some residual oxygen, and sulfite can help mitigate the effects of oxidation over a long aging period... Extending the shelf life beyond what's "adequate" for beer.

Cheers!

 

[piojo]

I'd suggest keeping molecular SO2 around 0.5-0.7ppm, based on pH

Thanks again for your info and links! My mead is high pH (4.62, and I will never again buffer without taking pH measurement first). I added 85-100 ppm sulfite, which still might not get me to the wanted level of SO₂ based on the charts I found. Do you know if these levels (low molecular sulfites but high levels of the other forms of sulfites) will hurt the yeast or cause other bad effects?

I can report back in a month about whether they carbonate.

 

[RPh_Guy]

Molecular SO2 is responsible for the antimicrobial activity. Around 0.4ppm is generally where bacteria and wild yeast are inhibited. Around 0.8ppm is generally where Sacc starts to be affected. I suggested the 0.5-0.7ppm range to avoid inhibiting bottle carbonation while still providing protection against wild microbes.

At your mead's pH it's difficult to achieve microbial stability with sulfite (you only have about 0.14ppm molecular SO2), but it will still protect against oxidation.
Off-flavor from sulfite is generally only a problem when there's high molecular SO2 (>1.0-1.2ppm), so you should be fine.
No worries.