Does pressure stop fermentation?

[Lord_Lycoperdon]

I was talking to guy who sells kombucha here in Oakland about how he bottles it. He just uses glass bottles with plastic lids. and that the pressure stops the fermentation and that you don't have to worry about it with kombucha.

Is this guy right? Is the same true about beer? Has anyone ever even had a bottle explode? (I never have...)

I searched the internet for answers and I found this article (below) but it is kinda confusing and I'm not sure how much pressure is in a bottle of beer~

Titre du document / Document title
How does yeast respond to pressure?
Auteur(s) / Author(s)
FERNANDES P. M. B. ;
Résumé / Abstract
The brewing and baking yeast Saccharomyces cerevisiae has been used as a model for stress response studies of eukaryotic cells. In this review we focus on the effect of high hydrostatic pressure (HHP) on S. cerevisiae. HHP exerts a broad effect on yeast cells characteristic of common stresses, mainly associated with protein alteration and lipid bilayer phase transition. Like most stresses, pressure induces cell cycle arrest. Below 50 MPa (500 atm) yeast cell morphology is unaffected whereas above 220 MPa wild-type cells are killed. S. cerevisiae cells can acquire barotolerance if they are pretreated with a sublethal stress due to temperature, ethanol, hydrogen peroxide, or pressure. Nevertheless, pressure only leads to protection against severe stress if, after pressure pretreatment, the cells are also re-incubated at room pressure. We attribute this effect to the inhibition of the protein synthesis apparatus under HHP. The global genome expression analysis of S. cerevisiae cells submitted to HHP revealed a stress response profile. The majority of the up-regulated genes are involved in stress defense and carbohydrate metabolism while most repressed genes belong to the cell cycle progression and protein synthesis categories. However, the signaling pathway involved in the pressure response is still to be elucidated. Nitric oxide, a signaling molecule involved in the regulation of a large number of cellular functions, confers baroprotection. Furthermore, S. cerevisiae cells in the early exponential phase submitted to 50-MPa pressure show induction of the expression level of the nitric oxide synthase inducible isoform. As pressure becomes an important biotechnological tool, studies concerning this kind of stress in microorganisms are imperative.
Revue / Journal Title
Brazilian journal of medical and biological research ISSN 0100-879X CODEN BJMRDK
Source / Source
2005, vol. 38, no8, pp. 1239-1245 [7 page(s) (article)]
Langue / Language
Anglais
Editeur / Publisher
Associação Brasileira de Divulgação Científica, Ribeirão Preto, BRESIL (1981) (Revue)
Localisation / Location
INIST-CNRS, Cote INIST : 14110, 35400013239836.0120

 

[kmack747]

At those pressures cited in that write up the bottle would not stand a chance and the beer would be grossly overcarbed. 50Mpa (500atm) is 7200psi. Its not the pressure that stops yeast its the lack of fermentables . If there is to much fermentables the beer will end up overcarbed and if the pressure gets to high or the bottle is weak.

Of all the beer that I have bottled over the years I have had one bottle bomb.

 

[JuanMoore]

Not sure about kombucha or what the actual pressures are, but since there are people who do closed pressurized fermentations, I'd say that pressure does not stop fermentation. Plenty of people have accidentally added too much priming sugar, or bottled beer prematurely, and had exploding bottles.

 

[Hoppus_Poppatopolis]

My wife makes kombucha. It's bottled after most of the fermentation is complete and not much pressure develops after that. Just enough to make a little fizz.

 

[Lord_Lycoperdon]

Thanks.

After thinking about it for a little bit I realized that he also refrigerates the drink when done and sure that slows down or stops the fermentation, but it's still kinda crazy that someone who sells a fermented drink told me that pressure stops the fermentation.......

 

[Jipper]

It will kill the yeast, AFAIK. I have heard from yeast manufacturers that PIS of 2-3 is enough to stress them and cause off-flavors, so I can only imagine at pressures higher than that would kill them. Try sending an e-mail to White Labs, they'll tell you for sure.

 

[lamarguy]

I have heard from yeast manufacturers that PIS of 2-3 is enough to stress them and cause off-flavors

Not sure what PIS is, but.... During storage, yeast will maintain improved viability if stored under low pressure (< 5 PSI).

However, pressure during fermentation does not cause off flavors. In fact, it reduces esters and the formation of certain undesirable compounds. For example, some breweries routinely apply 15+ PSI of top pressure to fermentation tanks during active fermentation. That is on top of the 6 - 10 PSI of hydrostatic pressure already present due to the sheer height of the unitanks.

Try sending an e-mail to White Labs, they'll tell you for sure.

Yes, do that.

 

[Jipper]

Yeah PIS ... you know, Pressure In Suds. Yeah thats it.

Well now I'm curious ... Thanks for the challenge to that, I hope I was wrong.

 

[lamarguy]

Well now I'm curious ... Thanks for the challenge to that, I hope I was wrong.

FWIW, I compiled a short summary for what the brewing literature says about fermentation top pressure.

 

[GilaMinumBeer]

Lord of Wolf Farts? Ha.

 

[SpanishCastleAle]

FWIW, I compiled a short summary for what the brewing literature says about fermentation top pressure.

lamarguy, what happens above 14.5 psi? I had read something on Probrewer that also implied 15 psi being an upper limit (I posted it today in Wortmonger's thread) but was curious why.

FWIW, lamarguy posted some more great info earlier in that thread on page 21.

 

[lamarguy]

lamarguy, what happens above 14.5 psi? I had read something on Probrewer that also implied 15 psi being an upper limit.

1 BAR (14.5 PSI) appears to be the practical upper limit for fermentation top pressure. According to the published experimental data, going past 1 BAR shows an unacceptable decrease in yeast growth (biomass) and, for most yeast strains, greatly increased acetaldehyde (green apple) production.

So, the yeast will certainly work past 1 BAR....You just won't like the resultant flavor and will likely fall short of the target gravity.

 

[AnthonyD]

The article states that the below 50 Mpa, yeast morphology is unaffected, and above 220 megapascals, wild-type yeast are killed... 220 Mpa is like 32,000 psi... I doubt the guy is bottling his kombucha at a level over ten times greater than the max pressure of commercial co2 cylinders.

 

[Magic]

I know i'm gravedigging, but it's not the pressure that will kill the yeast but the pH as a result of the dissolved CO2.

I wonder could this be used to have drinks finish sweet and carbonated? I don't think autolysis occurs either so no nasty yeasty taste.

 

[Vale71]

I know i'm gravedigging, but it's not the pressure that will kill the yeast but the pH as a result of the dissolved CO2.

I wonder could this be used to have drinks finish sweet and carbonated? I don't think autolysis occurs either so no nasty yeasty taste.

If you can drink something with 60-80 g/l of CO2 without exploding then all the more power to you. You'd have to find a way to drink directly from the spigot as something so heavily carbonated (over 10x normal carbonation levels!) cannot be poured into a glass at normal atmospheric pressure. As for autolysis not occurring, what do you think "entire cells" in the second graph points to if not autolysis?
Anyway, this is all theoretical as the pressures required at these carbonation levels will require fermentation tanks that are literally built like a tank...

 

[Magic]

I feel a bit silly for not comparing the amount of CO2 in the chart to what you would find in practice. In comparison, a bottle of coke has an estimated 6.2g/L of CO2 dissolved in it, according to some egghead over at stackexchange.

But, looking at that chart leads me to believe you don't need to be drinking from the spigot to kill the yeast with the produced CO2, you only need to carbonate it, and then store it for some amount of time. Viable cells drop even with a low amount of dissolved CO2, looks like 20% of viable cells died from ~6g/L CO2 in their given timeframe.
It would be an interesting experiment to try for sure.

 

[Vale71]

Surely you mean 0.6%? 6% is again 60g/l...

 

[Magic]

Haha yes. I do indeed mean 6g/L.

 

[siasconset]

If anyone is still following this thread, thanks to all, and I'm very confused. And I was a chemistry major!

For years after "accidentally" making really good cider by leaving a fresh gallon in the garage for 5 days, every autumn I made 8 or 16 1-liter soda bottles of the most delicious, sweet and fizzy cider I have everyhad, by pouring fresh-pressed preservative-free still cider into soda bottles with a tiny slice of organic, unwashed orchard apple inserted.

I knew nothing about brewing. No sanitizers (just dish soap and water wash), no sorbates or sulfites, no primary fermentation, no added sugars, nothing. The bottles always got harder and harder for a few days, then stopped. Refrigerated for weeks to months, nothing changed. No explosions. I always thought the CO2 pressure stopped the fermentation (there were still plenty of sugars left in the sweet final product) by shifting the equilibrium point for the fermentation reaction, just like in chemistry lab.

Now I don't know what stopped it. Lots of blogs and articles say you can't stop yeast fermenting until all the sugar's gone, even with hundreds of times the pressure in a soda bottle. Shrug.

I am now trying it with commercial cider yeast in a 1-gallon stainless steel keg or carboy, for the first time. Useful fact: with this method, the first 24 hours of fermentation brought internal pressure well above 30psi, but the sample tasted flat. Something I never considered: it takes days for fermentation-generated CO2 to dissolve back into the liquid, making it taste fizzy.

Cheers!