Yeast Starter & General Fermentation Question

[JimSY]

Hi all,

I'm hoping to brew 20 litres of Imperial Stout with an estimated original gravity of 1.070 and a final gravity of 1.017. While doing so I'm also going to make my very first yeast starter and I was wondering if I would have enough yeast with a single WYEAST 1028 London Ale smack-pack or whether I'll need to use more packs?

I ask because the instructions for the pack say that it is only good for 20 litres of wort with an OG of no greater than 1.060.

My second question is that I've recently brewed a Fuller's London Porter clone. I hit the OG of 1.058 but the re-hydrated Danstar Nottingham I used only managed to bring it down to 1.026 rather than the estimated 1.014 knocking a percent or so off the ABV. The beer has turned out fine (it's quite nice, actually!) but I was wondering what might have caused the poor performance?

Many, many thanks in advance, folks - Jim

 

[marshbrewer]

For your second question, my experience of Nottingham is that it over attenuates if anything, and I would expect a single pack to rip through a 1058 beer without problems. Did you mash at quite a high temp? I would be worried that this had stalled for some reason rather than finished.

 

[JimSY]

I mashed at 67c but I wasn't aware that mash temperature could have so much impact on the fermentation? The wort was well aerated and the initial fermentation was very vigourous (it even flooded the airlock and there was a fair few litres of head space to spare). There doesn't seem to be any negative effects on the beer, not that I can tell anyway. It just felt odd that, after such a good start, it stuck at 1.026.

 

[foxbat]

You will need to make a starter for your imperial stout. 1.070 isn't particularly ambitious so you shouldn't have trouble getting there as long as you normally get good efficiency with your process. The key is the sparge. You need to sparge well with a big grain bill. This calculator is my go-to for starters. Try to get a pack that's not more than a few months old and you won't have to do a multi-step starter. Some shops, e.g. the-home-brew-shop now tell you the manufacturing date in their ads. e.g. this is just a month old which is very fresh.

 

[Simonh82]

I mashed at 67c but I wasn't aware that mash temperature could have so much impact on the fermentation? The wort was well aerated and the initial fermentation was very vigourous (it even flooded the airlock and there was a fair few litres of head space to spare). There doesn't seem to be any negative effects on the beer, not that I can tell anyway. It just felt odd that, after such a good start, it stuck at 1.026.

Did you bottle or keg the ESB? If you bottled I'd look to move them somewhere cool and preferably keep them in a waterproof box of some kind. I'd be surprised if that Nottingham doesn't start up again and carry on fermenting. Bottle bombs seem quite likely.

 

[JimSY]

Did you bottle or keg the ESB? If you bottled I'd look to move them somewhere cool and preferably keep them in a waterproof box of some kind. I'd be surprised if that Nottingham doesn't start up again and carry on fermenting. Bottle bombs seem quite likely.

Bottled, I did anticipate some explosions but nothing! Spent two weeks under the stairs and the gravity still read 1.026, give-or-take, when I poured my first bottle. There's a slight yeasty off-taste and smell but if it's left a few minutes to breathe it clears-up.

Weird 'cos it's probably the tastiest beer I've ever brewed... :-)