Under pitched yeast

[dionbill]

Guys, scratching my head on this one. The last beer appears to be under-pitched. I did a double yeast starter getting my yeast count nearly double the recommended count. It fermented like crazy for a week through a blow off tube. Then settled down and now nothing. My gravity is still 20 points off. 1.030 instead of 1.010 target. I’m not sure why. But more importantly, is there a way to correct it? Will adding another test starter at this point finish the fermentation? I have another one I could do tonight if it would help. Thanks

Dion

 

[RM-MN]

Not enough information on this one. Grain bill, type of yeast pitched, mash temp, fermentation schedule all play a part in getting the attenuation you want.

 

[dionbill]

Sorry, 24 lbs grain (22lbs 2-row). Wyeast 1056. Mash temp in low 74F been fermenting in a SS conical fermenter for 9 days. Pulled off turb after day 2. Pulled again after 7 days. OG was 1.066 in 11 gal final vol into fermenter. I got an efficiency of 82%. We did loss our furnace for a few days which did drop the temp into the mid 60s for a few days. Hope that helps. Thanks.

 

[dmtaylor]

You racked it too much. 99% of the yeast was removed on Day 2. It should ferment out, it will just need more time. Warmth and swirling should also help. In future... don't rack it at all until it's done!

 

[Moriaty32]

Check your instruments... First order of business when your measurements are way off.

 

[kh54s10]

I hope that was a typo on your mash temperature. It should have been near 150F not 74F.

It's a conical so dumping the trub should not make a serious issue. But still I would let it ferment for at least 5-7 days before removing any.

I hope you are not measuring FG with a refractometer and not making a correction for the presence of alcohol.

For 1056. Mid sixties is a good fermentation temperature. I assume you were fermenting at 74. That is too high.

Recipe. If it is a stout that might be a good FG.

How many days fermenting now. If just 7, it might not be finished. I go 2 weeks to be sure it is done.

 

[dionbill]

Check your instruments... First order of business when your measurements are way off.

That was the first thing i did, measure it against water and it was right at 1.000. This was measured with a refractometer.

 

[dmtaylor]

Aha! Refractometer readings have to be adjusted in presence of alcohol. Go here:

http://seanterrill.com/2012/01/06/refractometer-calculator/

 

[dionbill]

Aha! Refractometer readings have to be adjusted in presence of alcohol. Go here:

http://seanterrill.com/2012/01/06/refractometer-calculator/

That was it. Those numbers get me to 1.012 fg. First time I used a refractometer for fg. Thanks a bunch guys for straightening me out in this. Cheers[emoji482]

 

[dionbill]

Let me ask a follow up question. Since fermentation appears to be complete after just nine days, when should I start to cold crash and keg? I know breweries go from boil to serve in 2 weeks (11 days ferment, 3 days bright tank). I will be using kegs as my bright tanks. Thoughts? Thanks again.

 

[LarMoeCur]

Guys, scratching my head on this one. The last beer appears to be under-pitched. I did a double yeast starter getting my yeast count nearly double the recommended count. It fermented like crazy for a week through a blow off tube. Then settled down and now nothing. My gravity is still 20 points off. 1.030 instead of 1.010 target. I’m not sure why. But more importantly, is there a way to correct it? Will adding another test starter at this point finish the fermentation? I have another one I could do tonight if it would help. Thanks

What exactly is a double yeast starter? 2L vise 1L? By my calculations you need a sex-tuple sized starter depending on what you call a regular starter. My pitching calculator calls for a 6.2L starter for 11 gallons of 1.066 ale. That large of size I would have done a step up process. Start with one vial in 1L of 1.035 wort (2 days) pitch that into a 5 to 6 L of 1.035 wort (5 days). Decant all the spent wort and pitch the yeast cake only.

You can try to save it. I would make a 2L starter when the starter is at high krausen (12-24 hours) pitch the entire 2L. The yeast have to be hyper active. You are pitching them into a toxic environment they must be actively fermenting to have any chance to survive.

 

[dionbill]

I used a vial with about 75B cells remaining. I did a 2L at 1.056 for about 30hrs. Let it settle and decant off most of the spent wort. Then I did a 2nd 2L starter using the settled yeast cake at 1.056 for another 24 hrs, immediately pitching it into the final 11 gallon brew. According to the brewers friend pitch calculator, I was well over the recommended pitch rates. I used a stir plate as well.

 

[Rhaop]

Reiterating what’s already been said but don’t rack off the yeast for at least 2 weeks what’s the rush? There are alot of folks that primary for a month, if you want to drop trub do that before pitching the yeast

 

[dionbill]

I have always done 2 week primary, 2 week secondary. With this one I am just experimenting.... I am playing around with trying to mimic a brewery setup of two week turnaround. Overpitch, fermenter for 11 days, crash for 3 days, keg, carbonate (quick carb) and serve. In my case, I’ll be crashing in a keg. Might be a total bust...

 

[LarMoeCur]

I used a vial with about 75B cells remaining. I did a 2L at 1.056 for about 30hrs. Let it settle and decant off most of the spent wort. Then I did a 2nd 2L starter using the settled yeast cake at 1.056 for another 24 hrs, immediately pitching it into the final 11 gallon brew. According to the brewers friend pitch calculator, I was well over the recommended pitch rates. I used a stir plate as well.

I see a few things in your process that may have contributed to under attenuation. Remember not all yeast cells act in the same manor. Some tire out really quickly, some have moderate stamina, and some are the energizer bunny and never stop.

On your initial starter 30 hours is not enough time to have the yeast settle to the bottom especially with a 1.056 wort. You decanted the wort containing the yeast cells with the most longevity (energizer bunnies). These are the yeast that get the beer to the finish line when the others have petered-out. They also clean up the yeast byproducts like diacetyl. You then stepped up the highly flocculent yeast in essence (cloning) doubling the count of the under achievers and dropping the number of the over achievers to almost nothing.

1.056 is to high of gravity for a starter. The recommend gravity is 1.035-1.040. The goal of starter is to grow yeast in the least stressful way possible. You can push the limits of a starter and still get a good starter but this will take more time to do it correctly. In my opinion trying to get 500 billion yeast count from one vial in 54 hours is setting your beer up for failure.

Good points above about dropping the yeast to early. That for sure didn't help.

 

[dionbill]

I agree that 1056 is to high but I was running out of time and was pushing the limits for sure. After the initial starter, I placed the flask in the fridge for about 24 hours to let it settle and then decanted of the yeast cake. Brought that back up to room temp and then pitched it into the second stater.

I should add that I actually didn’t under attenuate. I was using a refractometer for FG for the first time and didn’t account for the alcohol. Once I reran the numbers I had hit my FG so fermentation should be complete.

 

[dmtaylor]

Let me ask a follow up question. Since fermentation appears to be complete after just nine days, when should I start to cold crash and keg? I know breweries go from boil to serve in 2 weeks (11 days ferment, 3 days bright tank). I will be using kegs as my bright tanks. Thoughts? Thanks again.

I would wait a couple more days, then check final gravity again and make sure it's stable. Then keg.

 

[Rhaop]

I have always done 2 week primary, 2 week secondary. With this one I am just experimenting.... I am playing around with trying to mimic a brewery setup of two week turnaround. Overpitch, fermenter for 11 days, crash for 3 days, keg, carbonate (quick carb) and serve. In my case, I’ll be crashing in a keg. Might be a total bust...

I see, I think the biggest issue was racking after a couple days

If you like hefeweizen yeast that would be a great yeast to try a quick turn around on i have gone grain to glass in 7 days, kegging is required for obvious reasons

But yeah not knocking your experiment because that’s the only way you will master your system, good luck [emoji482]