Fast lager, pressure fermenting

[Corbières]

As an experiment I did a basic kit lager (Coopers European Lager) with 1kg DME - nothing else. Calculated it out - 21L to end up at 4.2%. SG 1.043 (actual) - target FG 1.011
Yeast was a harvested w34/70 (FIRST TIME I’ve done this) Fermented at 20c with spunding valve at 15PSI.
After 84hrs gravity was at 1.00
Crashed, kegged, force carb and tasted. It’s drinkable if nothing special.
Was it the harvested yeast, the temp or the pressure that had the biggest effect ?
Anyone offer an educated explanation please ?

 

[foxy]

As an experiment I did a basic kit lager (Coopers European Lager) with 1kg DME - nothing else. Calculated it out - 21L to end up at 4.2%. SG 1.043 (actual) - target FG 1.011
Yeast was a harvested w34/70 (FIRST TIME I’ve done this) Fermented at 20c with spunding valve at 15PSI.
After 84hrs gravity was at 1.00
Crashed, kegged, force carb and tasted. It’s drinkable if nothing special.
Was it the harvested yeast, the temp or the pressure that had the biggest effect ?
Anyone offer an educated explanation please ?

Well leave the pressure out of the equation, pressure suppresses yeast. So I would be putting it down to the high temperature and over pitching. Certainly went down to a low gravity.

 

[Corbières]

Well leave the pressure out of the equation, pressure suppresses yeast. So I would be putting it down to the high temperature and over pitching. Certainly went down to a low gravity.

Is there a way to measure harvested yeast ?

 

[smcc]

Is there a way to measure harvested yeast ?

yes if you have microscope, glass slides and a haemocytometer you can roughly calculate yeast count

 

[Corbières]

Any other advice for the rest of us please ?

 

[Thatscold]

I've done Coopers European lager before (fermented at 13C) and lagered for 3 months and it wasn't very special after that, so I wouldn't be too harsh on your outcome. I know others rate it, but for me it wasn't worth the wait.

Have you done this kit before? If so how is it different this way? ABV 5.5% must make a difference?

 

[Corbières]

Sorry was looking more for how FG ended up so low. Also seeking guidance on pitching rate for harvested yeast.

 

[Corbières]

I've done Coopers European lager before (fermented at 13C) and lagered for 3 months and it wasn't very special after that, so I wouldn't be too harsh on your outcome. I know others rate it, but for me it wasn't worth the wait.

Have you done this kit before? If so how is it different this way? ABV 5.5% must make a difference?

Not done it before. Wasn’t expecting that much was more interested in doing high temp under pressure to see results.

 

[Thatscold]

OK - understood. I'm interested in this myself as I have just got a fermenter king snub nose.

In case you haven't seen it Dr Hans on youtube covers lots on pressure fermentation

 

[nickjdavis]

Sorry was looking more for how FG ended up so low. Also seeking guidance on pitching rate for harvested yeast.

The pitching rate for any given beer is the same for harvested yeast as it is for fresh yeast.

However, to determine how much you need to grow your yeast by to reach the desired pitching rate you need to know how many viable yeast cells you have in your harvested yeast. To do this you need a microscope, slides and a haemocytometer as smcc said (he missed out that you might need some Methylene Blue as well. A haemocytomer is a special slide which has micro engraving on it which divides the slides into squares of a specific size. Under a microscope you can count the number of live cells within each square and then calculate (because each square has a specific volume of liquid in it) how many viable cells you have per milliliter or whatever.

Methylene Blue is a dye that you add to your sample which allows you to distinguish between dead yeast cells and live ones. When yeast cells die their cell walls break down and cannot resist the dye...so they appear blue. Live healthy yeasts cells resist the dye and appear clear.