Brewing beer in a heat wave

[Clarence]

I'm still not sure I get it. The hydrostatic pressure would depend on the depth alone, wouldn't it? Not the ratio of depth to volume. Is there an ideal depth for, say, à standard 20L batch?

Or maybe I've misunderstood the whole hydrostatic pressure thing, so off to research in my Boys' Book of Fluid Mechanics.

 

[Sadfield]

Yes depth alone for hydrostatic pressure. The ratio of surface area to volume for Co2 off gassing. Removal of Co2 is the important part as..

"Increasing concentrations of dissolved CO2 suppress yeast growth by unbalancing decarboxylation reactions (...) which are a fundamental step in either higher alcohol or acetyl-CoA synthesis" (Pires, 2015).

Which is why lagers ferment cleaner and slower, lower temperature retains Co2 in the wort. They are also more likely to retain undesirable sulphur compounds, that aren't scrubbed off by Co2.

More desirable fruity ester, less undesirable sulphur compounds. Although, some hop volatiles are lost, too.

 

[Clarence]

Yes depth alone for hydrostatic pressure. The ratio of surface area to volume for Co2 off gassing. Removal of Co2 is the important part as..

"Increasing concentrations of dissolved CO2 suppress yeast growth by unbalancing decarboxylation reactions (...) which are a fundamental step in either higher alcohol or acetyl-CoA synthesis" (Pires, 2015).

Which is why lagers ferment cleaner and slower, lower temperature retains Co2 in the wort. They are also more likely to retain undesirable sulphur compounds.

That makes sense. Can you recommend an idea fermenter shape for a standard homebrew batch of, say, 20-25 litres?

 

[Sadfield]

Try anything you have that reduces the wort depth noticeably from your normal fermenter. A plastic storage box was what I used initially. I use this know. L50 W30 D20cm 28L

I've been approaching this from the intention of promoting esters, rather than trying to navigate summer brewing. My limited experience is I've gotten away with some high temperatures. Fermenting both open or with a lid on.

Something that might be worth looking into, but I make no promises it'll be a magic bullet for all.

Here's some links mention FV geometry that I found useful, though.

https://www.google.com/amp/s/beerandbrewing.com/amp/4-reasons-to-try-open-fermentation/
https://www.beervanablog.com/beerva...de-la-senne-and-the-making-of-a-brussels-beer
https://wildflowerbeer.com/blogs/blog/process-e1-primary-fermentation-geometry
http://edsbeer.blogspot.com/2017/12/a-visit-to-brasserie-de-la-senne.html?m=1
https://www.beervanablog.com/beerva...de-la-senne-and-the-making-of-a-brussels-beer
https://wildflowerbeer.com/blogs/blog/process-e1-primary-fermentation-geometry

 

[Clarence]

@Sadfield
Thanks for all those references, which I'll have a good look at this afternoon. In the meantime, I've got one of these which I've never used (because the green plastic looked a bit iffy as though it might taint the beer with kryptonite). Absolutely ideal for a trial of shallow, open fermentation with a 20 litre batch, though. I've just salvaged some Wyeast West Yorkshire. Should be an ideal yeast for a trial.
https://braumarkt.com/Plastic-Fermenter-31-litres-with-Spigot-and-Airlock
Area of mine is 1257 cm2, area of yours is 1500 cm2 , but mine's a smaller batch.
Looking forward to this experiment.

 

[Sadfield]

Like Black Sheep's famously round yorkshire squares.

Having a quick Google at what Harvey's and Timothy Taylor do, and it's suggested they both pitch around 15-16c (which adds another issue with summer brewing, cooling). And on reference to TT fermentation reaches 70°F, which would give a 6°C rise over fermentation, which sounds plausible.

 

[Desmnd]

Hi. I did manage to clear the beer using a youngs gell finnings. It did eventualy clear but it took 14 days in the fermenter. Temperatures are getting cooler now so I should be okay. Will use a strong hi temperature yeast next summer heat wave. Also thanks to everyone her for their help.

I managed to get the KKs to hold their pressure with the washer underneith as it should be. I might try some beer frendly sealent instead of the petrolium jelly I have used for decades.

Next project is to boil some water with hops and use that to clean out the tins instead of just using boiling water. Just need a nice complementary hop for the beer.

I used to do it the propper way with the ingrediants and recipies from Dave Lines brewing beers like thouse you buy. Showing my age now.

 

[Desmnd]

5 gallon kits. has two tins of mollasses in them.

 

[Rugby Fan.]

Is the change in the amount of pressure achieved with a shallow FV at the ~20L level more than negligible?

Genuine question, me no physics good.

 

[Sadfield]

Is the change in the amount of pressure achieved with a shallow FV at the ~20L level more than negligible?

Genuine question, me no physics good.

Having read Edsbeerblog post about fermenter geometry, I did ask him on twitter (the missing tweet, I'm no longer on that black X abomination) whether a difference could be noticed at homebrew volumes. We both suspected the same as you, but according a Heriot Watt professor, there's a possibility it does.

 

[MashBag]

Is the change in the amount of pressure achieved with a shallow FV at the ~20L level more than negligible?

Genuine question, me no physics good.

At 20 litres it is the square root of duck all.
It is yet another commercial issue/practice that is irrelevant to small batches.... Bit like stainless steel fermenters

 

[Rugby Fan.]

Bit like stainless steel fermenters

Oi!

SS just give me piece of mind wrt to cleaning and sanitising

 

[MashBag]

Sorry forgot to mention "cleaning and sanitation"

 

[Jim Brewster]

Is the change in the amount of pressure achieved with a shallow FV at the ~20L level more than negligible?

Genuine question, me no physics good.

I would have thought it was negligible, but then I suppose it depends how sensitive yeast are to pressure and as we know they can be quite sensitive creatures. Atmospheric pressure is the same as the head of 34 feet of water, so a three foot deep bucket is only an additional 10% at the very bottom, and 5% on average. Short answer is, I don't know!

 

[Sadfield]

"Increasing concentrations of dissolved CO2 suppress yeast growth by unbalancing decarboxylation reactions (...) which are a fundamental step in either higher alcohol or acetyl-CoA synthesis" (Pires, 2015).

I think this vital point is being missed. It's not necessarily the pressure on yeast, we know people ferment under pressure, it's the difference in dissolved Co2 at different pressures, which alters yeast performance and behaviour. So the question becomes, does a deeper homebrew FV retain more dissolved co2 than a shallow one?

So, does a shallow vessel ferment with healthier growth and efficiency, than a deeper one, at the same elevated summer temperature? Producing more esters and less off flavours.

Looking at the point about co2 another way. Co2 is retained more at lower temperature. Lager ferments have slower growth, longer fermentation and often require lagering, long conditioning, to mellow out off flavours.