Fermentation hasn't started

[weiht]

Longer lag time probably due to more time needed for yeast growth... Too short a lag time isnt better as well, as the yeast may not have proper time to grow... 8-14 hrs is ok.

Just because we dont see anything doesnt mean there is nothing going on. The yeast only puts out CO2 and starts coverting sugars to alcohol after the initial growth, so airlock activity is also not a good indication the 1st 24 hrs.

Boils down to knowing how viable the yeast is prior to pitching. If u are pitching just a vial, allow it to warm up on the counter top for a few hours prior. Chris white also say to pop the vial to release pressure as it would add the yeast as it warms up and encourage it to be active again.

[guypettigrew]

If u are pitching just a vial, allow it to warm up on the counter top for a few hours prior. Chris white also say to pop the vial to release pressure as it would add the yeast as it warms up and encourage it to be active again.

It was left out of the 'fridge for about 5 hours before pitching. Unusually it didn't "pop" when I opened it.

Wonder what Guy's going to do with the surplus.

Now it's fermenting well I know there will be plenty of viable yeast at the end of the fermentation so I'll rinse it and keep it for another brew. I'll use yeast nutrient in the boil next time, though!

Guy

[Steveicky]

Steveicky wrote: I then pitched this directly into my next brew and to my shock it was fermenting within 2 hours.


How much?

I pitched about half the yeast cake from a previous brew. It was about 400ml into 50L of OG 1048, which I think was way over what i should have pitched based on the Mr Malty calcs.

Steveicky

[Eric]

Steveicky wrote: I then pitched this directly into my next brew and to my shock it was fermenting within 2 hours.


How much?

I pitched about half the yeast cake from a previous brew. It was about 400ml into 50L of OG 1048, which I think was way over what i should have pitched based on the Mr Malty calcs.

Steveicky

Yes, but did it make a worse brew?
I read that the yeast should grow and produce new cells. This happens while oxygen is present and when it's consumed, alcohol is produced. So, does that not mean the more oxygen that is dissolved in the wort, for any given amount of yeast pitched, the more yeast there will eventually be but the longer it will take to show? I don't think this is as simple as many suggest.

[guypettigrew]

I read that the yeast should grow and produce new cells. This happens while oxygen is present and when it's consumed, alcohol is produced. So, does that not mean the more oxygen that is dissolved in the wort, for any given amount of yeast pitched, the more yeast there will eventually be but the longer it will take to show? I don't think this is as simple as many suggest.

Complicated, this yeast stuff.

If there are lots of yeast cells, though, wouldn't it mean they just use the oxygen up more quickly? Then they'll start fermenting the sugars more quickly.

I've no idea, really. I just make the beer, chuck the yeast in, then drink it a few weeks later. Simples!

Guy

[darkonnis]

Oxygen is needed to a point, but that is because yeast are both aerobic and anaerobic. There is no preset formula for which is which, they are produced in one way or another. Oxygen is principally needed for reproduction (it speeds it up, a lack of doesn't mean it won't happen).
Also us homebrewers notoriously under pitch with yeast. Breweries chuck masses in as a general rule, so putting a bit of yeast cake in probably did no harm, besides it isnt possible to tell with out a scope how much is good and how much is bad and whats trub and whats yeast. I've had a few brews seemingly produce no trub, but I don't believe there wasn't any, more it was just the same colour and mixed in with the yeast cake.

[alix101]

http://www.amazon.co.uk/gp/aw/d/0937381969
Put it on your christmas lists.