WLP002 lower than 1.010?

[asidrane]

I brewed a 1.056 stout 12 days ago and used WLP002 that I had washed twice. The sample measured 1.010, but there was noticeable carbonation so I poured it into a cup and whisked it for a few minutes and let it settle. When I took the sample the second time it measured 1.006. Is it possible for WLP002 to get a beer this low, or do I likely have something 'extra' in my yeast? The sample tasted really good; with the amount of carbonation it had, I would have been happy to drink a pint.

 

[ajf]

Using washed 002, I usually get ~80% attenuation, and have no problems.

-a.

 

[MalFet]

I'd want to know more about your grist composition. You're looking at about 90% attenuation, which is mighty high...especially for that yeast. But, if it tastes good, hey...no worries.

 

[bleme]

You may have just developed a new strain! Patent that baby!!! :-D

 

[asidrane]

I'd want to know more about your grist composition. You're looking at about 90% attenuation, which is mighty high...especially for that yeast. But, if it tastes good, hey...no worries.

Here's the recipe:
2-row: 2 lbs
Crystal 80: 1 lbs
Black Patent: 14 oz
CaraPils: 8 oz
Munich (light): 8 oz
White Wheat: 8 oz
Roasted Barley: 2 oz

I mashed this in 3 gallons of 150 degree water for 55 minutes and sparked with 1.5 gallons. When I got to a boil, I added 3.3 lbs LME and topped off the fermenter to get to 5 gallons at the end.

 

[TarheelBrew13]

It's possible to get below 1.010 with that yeast. I'd double check the readings to make sure your reading the temp and hydrometer correctly and adjusting for the hydro calibration temp.

I'd be really surprised if it was infected.

 

[MalFet]

I'd recommend another reading, as well. 1.006 is mighty low for that grist.

 

[bierhaus15]

It is actually pretty common to get 85-90% attenuation with washed wlp002 yeast. One of the pro brewers I once talked to, who uses this yeast, said they don't go more than a few generations from the same culture since this strain is very prone mutating. It is a pretty tricky strain to get consistent results when repitching.

 

[Stauffbier]

I've only used wlp002 once for a chocolate stout, and unfortunately that batch is infected with wild yeast or bacteria that won't stop eating unfermentables in the beer. After 8 weeks in the bottle it tastes awful, the gravity is dropping, the beer is getting very dry, and is gushing real bad. When I open a bottle and de-gas I also get a reading of about 1.006. I hate to dump a batch, so it's just sitting in my fridge taking up space. I'm going to try making a BBQ marinade with some and see if it works. Otherwise, I'm probably going to have to water the grass with it...

 

[bierhaus15]

I've only used wlp002 once for a chocolate stout, and unfortunately that batch is infected with wild yeast or bacteria that won't stop eating unfermentables in the beer. After 8 weeks in the bottle it tastes awful, the gravity is dropping, the beer is getting very dry, and is gushing real bad. When I open a bottle and de-gas I also get a reading of about 1.006. I hate to dump a batch, so it's just sitting in my fridge taking up space. I'm going to try making a BBQ marinade with some and see if it works. Otherwise, I'm probably going to have to water the grass with it...

This is actually a common problem and is not always infection related. Because this strain is such a fast flocculator, the yeast often reactivate in the bottle due to an influx of oxygen and sugar during the bottling process. Once awake the yeasts will take the gravity down below the F.G. Kegging is one way to get around this. If you don't want to keg, you can rouse the yeast a few times during fermentation (from the bottom) to ensure your yeast isn't flocculating before they've eaten all the sugar they can handle.

 

[Stauffbier]

This is actually a common problem and is not always infection related. Because this strain is such a fast flocculator, the yeast often reactivate in the bottle due to an influx of oxygen and sugar during the bottling process. Once awake the yeasts will take the gravity down below the F.G. Kegging is one way to get around this. If you don't want to keg, you can rouse the yeast a few times during fermentation (from the bottom) to ensure your yeast isn't flocculating before they've eaten all the sugar they can handle.

I roused my yeast three times and raised my temps to around 70F for 4 days and still couldn't get my FG down any further. It finished at 1.018 and I was expecting 1.016. It was stable at 1.018 for almost 18 days, so I finally decided to bottle. Unfortunately I'm still not set up for kegging..

 

[asidrane]

It's possible to get below 1.010 with that yeast. I'd double check the readings to make sure your reading the temp and hydrometer correctly and adjusting for the hydro calibration temp.

I'd be really surprised if it was infected.

I checked the gravity reading twice before i whisked the sample and twice after. I came up with the 1.010 and the 1.006 readings both times. The temperature of the sample was 68 and I tested the hydrometer in water and it registered 1.000

 

[nulfis]

It is actually pretty common to get 85-90% attenuation with washed wlp002 yeast. One of the pro brewers I once talked to, who uses this yeast, said they don't go more than a few generations from the same culture since this strain is very prone mutating. It is a pretty tricky strain to get consistent results when repitching.

Yeah, I just recently noticed this happen with the 002 strain I've been using. I think my saved strain is on its 4th generation now, and the last brew I used it on had a completely different fermentation profile than previous uses. I usually get a good bit of "boiling" going on when I use WLP's yeast, but this time, the 002 formed a giant carpet on top of the beer and stayed that way until it dropped. My attenuation stayed within the predicted FG though, probably around 80%, I was just surprised to see it act so differently in the carboy.

 

[asidrane]

I decided to calibrate my hydrometer in water today and it was off. I have another hydrometer and it measured accurately. I drew a sample again and measured with the bad hydrometer and got 1.010. When I rested with the good hydrometer it measured 1.015.