Spunding

[brenmurph]

Bren, I saw your pic. Need to be able to finely adjust pressure tho!

ok now I feel like a right fukin idiot

That's a pressure reducing valve. My central heating system has one, but it's not the same thing as a pressure relief valve.

I think we need a pressure relief seminar..........theres a slight difference between a co2 reg, a PR valve and a flow control valve...someone will have an accident one day!

Tube ur central heating has a PR valve with a red or blue cap on it its set to either 3 or 6 bar, that valve is fully adjustable and if spring is replaced can be given any range for any purpose. But as cider says my pen is a way better and cheaper "pressure relief / control device!  and is fully and finely adjustable in tiny increments of about 1/10 of a psi believe it or not by sliding the orange cable tie a ml or 2...its exceptionally efficient.

[Ciderhead]

Bren, I saw your pic. Need to be able to finely adjust pressure tho!

ok now I feel like a right fukin idiot

That's a pressure reducing valve. My central heating system has one, but it's not the same thing as a pressure relief valve.

I don't care what it is, it works and best of all it was freeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[Ciderhead]

Checking net tonight on fermenting under pressure and
Its all about fermenting
1) at higher temperatures
2) Higher gravity beers
The higher prevents pressure prevent the formation of esters and fusel alcohols that might normally appear.
So the big boys do this and dilute back their beer allegedly!
it transpires very high pressures don't suit all yeasts, if fact it puts some under mechanical stress by  holding in a lot of CO2, this creates chemical/osmostic stress on the yeast, if you are going to stress the yeast make sure you start with plenty, that's viable, and add nutrient, lack of care will result in the expected under-attenuation not great for harvesting either .

in any case we need to get some of this;
http://www.whitelabs.com/beer/strains_wlp925.html

Not sure I am brave enough to do in primary but definitely giving secondary a go.

[Jacob]

Yeast is killed above 10 psi. Or is it?

15 is the magic number ...

[johnrm]

Consider this: Bottle Bombs - What pressure is required to produce one? My guess is that the yeast is active up to and beyond the pressure containable by a capped bottle. Also, we have seen (Posted elsewhere here?) cases where mini-kegs have deformed under pressure.

Surely the pressre at which yeast isaffected depends on the Yeast strain.

[Jacob]

Where did you get that number?

That's the number I've seen in few places like:
Homebrewtalk,
Homebrewersassociation,
Aussiehomebrewer

[johnrm]

Well, you can, you just can't measure it with your doo dad.