Will fermentation re-start?

[Chris Grubb]

Brewed a porter on Saturday. Pitched my hydrated London ESB.
Yesterday morning it was bubbling away and fermenting good at about 65 degrees.
I bumped it up to 68 and left.
Went back today and no signs of fermentation and at 61 degrees.
I had forgot to plug in the heater to the strip on my controller. I plugged it up and shook it around some.
Did I kill the yeast or will it wake back up when the temperature gets up to where it needs to?

 

[day_trippr]

The advertised optimal temperature range to run that yeast is 18°C(65°F) to 22°C(72°F).
So you likely just slowed them for a bit, once you warm the beer back to their happy place if there's more work to do they'll do it...

Cheers!

 

[rburrelli]

Brewed a porter on Saturday. Pitched my hydrated London ESB.
Yesterday morning it was bubbling away and fermenting good at about 65 degrees.
I bumped it up to 68 and left.
Went back today and no signs of fermentation and at 61 degrees.
I had forgot to plug in the heater to the strip on my controller. I plugged it up and shook it around some.
Did I kill the yeast or will it wake back up when the temperature gets up to where it needs to?

Temps have to go pretty to kill yeast. Warm it back up and you should be fine.

 

[foolsbrew]

Fermentation shouldn't stop at 61F, only slow down a bit. That temperature isn't even enough for them to go dormant, lots of people ferment ales at this temperature.
Ale yeasts can work pretty fast, it isn't unheard of for the majority of fermentation to be done after 24 hours at warmer temperatures. If it was mostly over anyway, it is normal to see no apparent signs of fermentation since there is little left to ferment and it is working slower now due to the temperature.
Perhaps the yeast is in shock. It can happen for a variety of reasons, like a significant heat change in a short amount of time. This can happen even in the optimal temperatures, you just need to heat or cool it fast enough. If this is the case, wait a bit and they should get back to work.

I'd guess, either the fermentation is actually mostly done and it is still fermenting, just slowly, or you need to wait a bit for them to wake back up.

If they went dormant for some reason(the temperature being 61F isn't a good reason by itself) and there is little left to ferment, they may not wake up on their own. Add a small amount of sugar/water mix(or anything fermentable) and that should wake them back up to complete the fermentation.

 

[Chris Grubb]

Fermentation shouldn't stop at 61F, only slow down a bit. That temperature isn't even enough for them to go dormant, lots of people ferment ales at this temperature.
Ale yeasts can work pretty fast, it isn't unheard of for the majority of fermentation to be done after 24 hours at warmer temperatures. If it was mostly over anyway, it is normal to see no apparent signs of fermentation since there is little left to ferment and it is working slower now due to the temperature.
Perhaps the yeast is in shock. It can happen for a variety of reasons, like a significant heat change in a short amount of time. This can happen even in the optimal temperatures, you just need to heat or cool it fast enough. If this is the case, wait a bit and they should get back to work.

I'd guess, either the fermentation is actually mostly done and it is still fermenting, just slowly, or you need to wait a bit for them to wake back up.

If they went dormant for some reason(the temperature being 61F isn't a good reason by itself) and there is little left to ferment, they may not wake up on their own. Add a small amount of sugar/water mix(or anything fermentable) and that should wake them back up to complete the fermentation.

I got it back up to temp and no noticeable activity. Pulled a sample yesterday and it was at 1.031 2 days after pitching,where OG was 1.060. I’m going to give it another few days and pull another sample. Hopefully it is still working and will get to something respectable.
If not, this would be my 2nd porter in a row that fermentation stuck on. Never had a problem with any other kind. Is that common with porter ingredients?

 

[bracconiere]

i'd think 1.031 from 1.060 after two days is damn good?

 

[IslandLizard]

this would be my 2nd porter in a row that fermentation stuck on. Never had a problem with any other kind. Is that common with porter ingredients?

No, they should ferment out as any other beer.

Was your fermented sample measured with a hydrometer or refractometer? Did you taste it?

Extract or all grain?
Can you post your recipe or a link to it?

Now that ESB yeast will leave a residual sweetness (and "body"), due to its inability to ferment maltotriose, leaving a higher gravity in the finished beer, but shouldn't be anywhere near half of your OG.

The optimal temperature range for LalBrew® London yeast when producing traditional styles is 18°C(65°F) to 22°C(72°F)
LalBrew® London does not utilize the sugar maltotriose (a molecule composed of 3 glucose units).
Maltotriose is present in wort in an average 10-15% of all malt worts. The result will be fuller body and residual sweetness in beer. Be advised to adjust gravities and mash temperatures according to desired result.

 

[Chris Grubb]

No, they should ferment out as any other beer.

Was you fermented sample measured with a hydrometer or refractometer? Did you taste it?

Extract or all grain?
Can you post your recipe or a link to it?

Now that ESB yeast will leave a residual sweetness (and "body"), due to its inability to ferment maltotriose, leaving a higher gravity in the finished beer, but shouldn't be anywhere near half of your OG.

Measured with hydrometer, which has been verified. Didn’t taste it yet, was going to see what it tasted like next sample I pulled. This is an all grain brew.

 

[foolsbrew]

I got it back up to temp and no noticeable activity. Pulled a sample yesterday and it was at 1.031 2 days after pitching,where OG was 1.060. I’m going to give it another few days and pull another sample. Hopefully it is still working and will get to something respectable.
If not, this would be my 2nd porter in a row that fermentation stuck on. Never had a problem with any other kind. Is that common with porter ingredients?

1.06 isn't high enough to be a problematic environment for the yeast.
I'd check the equipment. Are your thermometers correct? Maybe it was infact heated or cooled down far outside the range. Maybe you mashed at too high a temp leaving you with more unfermentable sugars than you expected(even in this case 1.03 is still too high, but at least that's explainable then).
Sometimes you just get unlucky, but if it's the second time in a row, I'd check the process. If the process looks fine, I'd check if one of the equipment is faulty.

By the way, another unlikely guess: If you are using a bucket with a spigot to take a sample and the spigot is too low or you have too much trub for whatever reason, that would create a faulty sample.

 

[kh54s10]

4 days, and on the low end of the temperature scale. It SHOULD be fermenting slowly. And at 4 days signs of slowing should also happen. I don't really even look at mine except to be sure something is happening for 2 weeks. Then I check for completion.

I bet it is still going fine, just not showing a lot of activity.

 

[Chris Grubb]

4 days, and on the low end of the temperature scale. It SHOULD be fermenting slowly. And at 4 days signs of slowing should also happen. I don't really even look at mine except to be sure something is happening for 2 weeks. Then I check for completion.

I bet it is still going fine, just not showing a lot of activity.

I am pulling samples from the sampling port on my CF5 conical.
Checked it again today, day 6, and there hasn’t really been any change since day 2. Been at 70 degrees since. It was about 1.030 or maybe 1.031 on day 2 and day 6 is about 1.030 maybe 1.029.
I tasted it, and it tastes decent for a flat low alcohol porter, just not sure why fermentation stalled.
I mashed right at 154 for an hour.
Original recipe was:
10 pounds maris otter
1 pound brown malt
1 pound crystal 40
1 pound chocolate
3 ounces roasted barley

Rehydrated London ESB ale and had a good cake when I pitched it in the fermentor and oxygenated. Vigorous activity within 12 hours then nothing sense.
Some of the grain is a few months old, would that have anything to with it?

 

[IslandLizard]

Some of the grain is a few months old, would that have anything to with it?

Nah, but the malt was likely much older when you got it. Malt is fine for years, stored cool and dry.
Which maltsters MO is it? Where did you get it?

Have you tried rousing the yeast? You could bubble CO2 through your racking port, arm pointing down, blow off valve on lid open. Or through the dump port.
Make sure to pressurize the CO2 hose before opening the valve/port. Last thing you want is flooding your regulator with beer backing up.

I've never tried with a partially fermented/stalled beer, but perhaps do a (modified) fast ferment test with the beer you now have:
http://braukaiser.com/wiki/index.php/Fast_Ferment_Test

For that, take another sample, 4-8 oz, put in a quart sealable jar (mason jar) so you have ample headspace. Add 1/2 tsp of some dry bakers (bread) yeast, lid, and shake, and release lid enough so it can vent. Cover with some sanitized plastic wrap or aluminum foil to keep bugs out. Keep in warm place >70F. Shake or swirl a few times a day. See where that goes.

 

[kh54s10]

Puzzling.... I see nothing anywhere that would cause a problem. Not the getting cool at the start of fermentation, the recipe, the handling of the yeast, mash temperature, age of the grain..... Nothing.

Only thing I can think of is to pitch more yeast.