Bottom fermenting: a temperature question...

[morethanworts]

Should you pitch lager yeast at a top-fermenting temperature and then lower it only when the airlock is bubbling, or should you lower it straight away to 'lager' figures (maybe 10-15C)? The info on my yeast sachet, and even the makers pdf info sheet, doesn't quite go into that detail.

I'm currently waiting to see if my rehydrated yeast (2 packets of Maurivin Lager 497) are about to do the business on a Brupaks Special Lager kit. I pitched the rehydrated wort mid-afternoon yesterday at 17C, but allowed the wort to drop to around 13-15C soon afterwards. I had rehydrated the dry yeast at 35C as per instructions, cooled with a little wort to 21C in 20 mins and then pitched promptly into the 17C wort]

Nothing happening yet, though the little I can see about this yeast, other than it may be the same strain as Superior (Dry) Lager Yeast, and that it can be a slow starter. I've turned it up to 16-17C to be on the safe side for now, but am I right to do so?

 

[Good Ed]

I presume you followed THIS re hydrate dried yeast with water also if you pitched at 17C you should be ok, but fermenting temperature is 10-15C, so that is whre you should be, don't turn up the temperature, but keep it constant. Lager yeasts sometimes take a bit longer to get going so just be patient.

 

[morethanworts]

I presume you followed THIS re hydrate dried yeast with water also if you pitched at 17C you should be ok, but fermenting temperature is 10-15C, so that is whre you should be, don't turn up the temperature, but keep it constant. Lager yeasts sometimes take a bit longer to get going so just be patient.

Hi, Good Ed

Yes, that's what I followed: the Maurivin info sheet. But I also saw point 2 on this link http://www.homebrewing.org/How-to-Make- ... _42-1.html

The Maurivin sheet doesn't elaborate on how soon after the recommended >15C pitching temperature the wort can/should be lowered to 10-15C.

 

[zgoda]

Usual advice is 1c per hour after signs of fermentation.

But I prefer to pitch more yeast bit below fermentation temp and allow to rise naturally. It's much easier to cool the wort to 9c than already fermenting beer from 15c to 10c.

 

[morethanworts]

Well, I've split the difference and it should be around 13C, though I'm not lifting the lid to check. The probe is in the water bath and I did tests in (inactive) water for a couple of days with this set up.

I'm not fretting yet It's about 42 hours since pitching and no bubbles in the airlock.

The 35C rehydrating yeast only came down a few degrees in 10 mins, so I sat it in a cool bowl for a few minutes more and then mixed in some wort, as per instructions. Although the instructions said not to expose the yeast to temperature shock, they did not quantify that. Though to get from 35 to 17-18 in under 30 mins max (the maximum time given) means a quick drop anyway. Mine may have dropped 10C in 2 or 3 mins when I mixed in the bit of wort to cool it. I hope that hasn't done any harm...

 

[morethanworts]

No movement in the airlock, but quite a bit of krausen (unexpectedly): I peeped through the airlock at 36 hours [EDIT - was 48hrs] yesterday and was reassured. The temperature in the middle of the FV was 10-11C (probe in the water bath was set to 10.5), so all good there.

Perhaps my vessel is not completely airtight and these lagers just go slow enough not to trouble the airlock!

 

[rpt]

Perhaps my vessel is not completely airtight and these lagers just go slow enough not to trouble the airlock!

Almost certainly so. Currently lagering some lager - when it was first in the FV I was convinced it wasn't working and I'd pitched the yeast too cool, but the hydrometer confirmed that it was in fact fermenting very nicely.