Imperial Stout yeast

[Regitynot]

Hi. I started an imperial stout on saturday OG 1113 and used 2 packs of Mangrove Jack's M42 pitched at 20C and fermenting at a controlled 18C.
Did not take off as I expected but by Tuesday morning reading 1070.
Will leave it for a couple of days and re test but activity from blow off tube has almost stopped.
Any suggestions welcome.

 

[Nosybear]

Hi. I started an imperial stout on saturday OG 1113 and used 2 packs of Mangrove Jack's M42 pitched at 20C and fermenting at a controlled 18C.
Did not take off as I expected but by Tuesday morning reading 1070.
Will leave it for a couple of days and re test but activity from blow off tube has almost stopped.
Any suggestions welcome.

If your OG was 1113 and your Tuesday morning reading was 1070, your beer is fermenting. My hypothesis given your posting in a beginner forum (no insult intended) is you severely underpitched the yeast and then it ran out of oxygen. High gravity fermentations are tough, even for experienced homebrewers. I understand the desire to do difficult beers but you picked a doozy! Fermenting an Imperial anything:
1. Grow a very big starter of alcohol tolerant yeast, as in make a beer at around 1045-1050, lightly hopped, and use all the yeast from it to ferment the beer.
2. Oxygenate, not aerate, the wort before pitching.
3. Oxygenate it again after about 18 hours.
4. Keep the temperature cool through about half the fermentation to control fusel alcohols.
5. After half the fermentation, let the temperature rise to dry the beer out as much as possible.
6. Swirl the trub up every day or so to keep the yeast suspended.
7. If your yeast gives up, use a high-gravity yeast such as champagne yeast to complete the fermentation.
8. Let the beer age to smooth out the inevitable harsh flavors.

Your post was a bit vague so if you did any of these things and I missed it, I apologize.

 

[Regitynot]

If your OG was 1113 and your Tuesday morning reading was 1070, your beer is fermenting. My hypothesis given your posting in a beginner forum (no insult intended) is you severely underpitched the yeast and then it ran out of oxygen. High gravity fermentations are tough, even for experienced homebrewers. I understand the desire to do difficult beers but you picked a doozy! Fermenting an Imperial anything:
1. Grow a very big starter of alcohol tolerant yeast, as in make a beer at around 1045-1050, lightly hopped, and use all the yeast from it to ferment the beer.
2. Oxygenate, not aerate, the wort before pitching.
3. Oxygenate it again after about 18 hours.
4. Keep the temperature cool through about half the fermentation to control fusel alcohols.
5. After half the fermentation, let the temperature rise to dry the beer out as much as possible.
6. Swirl the trub up every day or so to keep the yeast suspended.
7. If your yeast gives up, use a high-gravity yeast such as champagne yeast to complete the fermentation.
8. Let the beer age to smooth out the inevitable harsh flavors.

Your post was a bit vague so if you did any of these things and I missed it, I apologize.

If your OG was 1113 and your Tuesday morning reading was 1070, your beer is fermenting. My hypothesis given your posting in a beginner forum (no insult intended) is you severely underpitched the yeast and then it ran out of oxygen. High gravity fermentations are tough, even for experienced homebrewers. I understand the desire to do difficult beers but you picked a doozy! Fermenting an Imperial anything:
1. Grow a very big starter of alcohol tolerant yeast, as in make a beer at around 1045-1050, lightly hopped, and use all the yeast from it to ferment the beer.
2. Oxygenate, not aerate, the wort before pitching.
3. Oxygenate it again after about 18 hours.
4. Keep the temperature cool through about half the fermentation to control fusel alcohols.
5. After half the fermentation, let the temperature rise to dry the beer out as much as possible.
6. Swirl the trub up every day or so to keep the yeast suspended.
7. If your yeast gives up, use a high-gravity yeast such as champagne yeast to complete the fermentation.
8. Let the beer age to smooth out the inevitable harsh flavors.

Your post was a bit vague so if you did any of these things and I missed it, I apologize.

Thanks for that. I have very successfully made this recipe before but with a lower grain bill and it fermented out to a predicted 10% and was an excellent beer. I thought I would up the ante a little.
Will report back in a couple of days....still learning! Cheers

 

[BOB357]

I agree with Nosybear. 2 packets is under pitched. MJ's10 gram packets have about 180 billion cells at best. A proper pitch for that gravity would be about 380 billion cells. Keep in mind that, even dry yeasts lose viability over time, especially if not handled properly. I always figure 150 billion cells/packet just to be safe. Cross your fingers and be patient.

 

[Regitynot]

I agree with Nosybear. 2 packets is under pitched. MJ's10 gram packets have about 180 billion cells at best. A proper pitch for that gravity would be about 380 billion cells. Keep in mind that, even dry yeasts lose viability over time, especially if not handled properly. I always figure 150 billion cells/packet just to be safe. Cross your fingers and be patient.

 

[Regitynot]

Now at 1046 5 days since pitching yeast. Ramped up to 20c and bubbling every 5 seconds.
Thanks for your guidance guys. Much appreciated. Forgot to mention at start its 15L batch too, my apologies.
Should I need to use champagne yeast is it likely to take my target FG below 1022 and would this over dry it? Cheers

 

[BOB357]

2 packets is just about right for 15 liters at that gravity. I hope you rehydrated the yeast, For a beer that big, you need to give the yeast every bit of TLC you can.