Bitter yeasts

[Aleman]

Aleman... you'll have to explain to us again why you use such a dilute wort ?

All the advice says around 1.035 - 1.040 ? :wha:

Where is the :sigh: smiley? I suppose I'll have to settle for

Yeast can respire aerobically (With Oxygen) and anaerobically (Without Oxygen) when as a by product they produce alcohol, as opposed to higher organisms such as ourselves who produce Lactic Acid . . . nowhere near as much fun. Now the pathway that uses oxygen (Krebs cycle) produces 16 times (IIRC) the amount of energy as the pathway producing alcohol for every glucose molecule consumed so is much more efficient. Now you would assume that putting a starter on a stir plate and blowing air into it would mean the yeast would work aerobically . . . Its a perfectly logical sound assumption . . . except they don't :shock: What Crabtree (et al I Think) discovered was that when the level of glucose in the substrate reached 4% the little b*ggers changed to anaerobic respiration :wha: And this was in spite of them being fed higher concentrations of oxygen, a state known as substrate inhibition. This is known as the Crabtree effect.

A 4% glucose solution is round about 1.012, so to get the most efficient yeast reproduction, your starter gravity should be at or below this level . . . . I suspect that using a higher gravity starter will still achieve good yeast growth, its just that the lower gravity one will get there faster. . . . and the yeast will probably be in better condition having not been stressed.

I do know that Whitelabs (and Lallemand) use this method for yeast production, but just before packing/drying, they turn the oxygen/air off so that the yeast switch themselves into anaerobic mode so that they are ready to start turning all of the sugar into alcohol when they are pitched.

OK :thumb:

 

[Vossy1]

So a lower gravity starter is

A) better for the yeast
B) cheaper
C0 it's faster

Would that equate to 60g's of dme in 2ltrs then (1.040 = 200g DME in 2ltrs......200/40 X 12 = 60g in 2ltrs)

 

[Aleman]

Would that equate to 60g's of dme in 2ltrs then (1.040 = 200g DME in 2ltrs......200/40 X 12 = 60g in 2ltrs)

If thats the maths, I use excess wort from brewing so dilute it accordingly

 

[mysterio]

That's gold, Aleman - thanks for that.

Any caveats before I start using your method? Do you still get the same number of cells as a 1.040 wort or will I have to build yet bigger starters?

 

[Aleman]

Any caveats before I start using your method? Do you still get the same number of cells as a 1.040 wort or will I have to build yet bigger starters?

Not really, I'm using a stir plate, and blowing HEPA filtered air into the flask (not the solution just to flush the flask). I've not noticed any difference in qty of yeast produced but I have not done a cell count to check . . . In fact I think that I end up with visibly more sediment using the low gravity method than I did before.

One problem is that you can't pitch the entire starter as it is considerably weaker than any beer you are going to add it to. . . . Just make a Daabs (Ahem) flying starter on brewday to deal with that issue.

 

[mysterio]

If this works it's going to make my lager starters much less of a PITA :pray:

 

[Vossy1]

Well I stuck the WLP O23 in the kegerator last night, cranked it dowm to 1 deg c and hey presto, a lovely yeast layer today

Resistance is futile :lol:

 

[Vossy1]

This yeast is a reet dodgy character.
I hated the aroma given off in the starter...it was very sulphury and not at all nice.
Now it's in a fv full of beer it smells absolutely fantastic, no sign of sulphur....where's that straw :hmm: :whistle:

 

[russt1969]

..where's that straw :hmm: :whistle:

I borrowed it Vossy. You want it back then I guess????? :lol:

 

[Vossy1]

:lol:

I just made do with the trial jar again...slumming it :lol:

 

[Vossy1]

How long does WLP 023 usually take to ferment out guys?

My bitters gone from 1.050 to 1.024 in 3 days (I should say I only checked it on the 3rd day), and in the last 2 it's dropped 4 points to 1.020. It needs to drop another 7 points for my liking and it's not looking good.
Presently sat at 21.8 deg c and bubbling every 2 seconds.

I've just had a good look at the whitelabs website and it warns of loss of this top cropping yeast via the blow off tube.
I DID lose a lot of yeast from the fv. For the future I would like to find a way of avoiding this loss. To my mind, the only way of doing it is to use an oversized fv, or find some way of collecting the yeast in a sanitised way and re-introducing it.

Either way it looks like on this batch I'm gonna have to try and knock some of the C02 out of solution and rouse.

 

[BrewStew]

you're not having much luck with this group brew thing are you?

 

[Aleman]

I probably didn't get this problem because I fermented 50L in a 100L FV, and followed it up with a 70L brew in the same fermenter.

Certainly both my brews fermented out with alacrity

 

[Vossy1]

you're not having much luck with this group brew thing are you?

:lol:

I probably didn't get this problem because I fermented 50L in a 100L FV, and followed it up with a 70L brew in the same fermenter.

Aleman out of interest, a 100ltr stock pot is roughly 50 x 50 cm. Would you envisage the low width to height giving me the same problem fermenting a 60 ltr brew? A 60ltr brew would be 20cm below the top.
The alternative is a 120ltr plastic jobby which is 50cm wide by 78cm tall...it will be a push in my fv cupboard but give the yeast plenty of room to grow

 

[Aleman]

Well I didn't get anything escaping when I did 70 and 83L brews in the 100L pot . . . Certainly I remember using FD20P antifoam on the 50L IPA brew . . . don't think I did on the 70L and I know I didn't on the 83L.

I do know someone who ferments 60L in a 65L plastic fermenter . . . but then he does use a little more FD20P than I do . . . when I remember to add it :evil:

 

[steve_flack]

Vossy, I think you need to take a look at getting some antifoam (FD20P). I use it as a matter of routine and I've never had a problem with yeast escaping the fermenter.

And to answer the obvious question....no it doesn't affect the foam in the glass (probably makes it better actually as the foam promoting compounds stay in your beer and not on the floor).

 

[Vossy1]

Thanks guys, I didn't even know that product existed
I'll have a look round for it today :thumb:

 

[steve_flack]

Here's what you're looking for

http://www.hopandgrape.co.uk/catalog/de ... BEE2155270

 

[Vossy1]

Cheers Steve, picking some up tomorrow

Do you guys just apply it to the fv as per the instructions ?
I ask, as it doesn't mention fv use on the label, from what I can see.

 

[steve_flack]

You can add it diluted with water with a sprayer but I use a dropper. It's also very handy when boiling starters to stop boil overs.