Sunday, October 23, 2011

Fermentation Woes

Homebrewing is a humbling activity. Just when you think you've done everything you can to ensure your beer will turn out as you planned, something unexpected comes along and undoes everything you worked so hard to get right. In my case, I've had two recent batches go pear-shaped on me with fermentation issues.

The first problem was with the dark mild I brewed just over a week ago. Like always, I pitched a healthy two quart starter (decanted) of wyeast 1968 London ESB into the 64F wort and set my fermentation chest for 68F. Normally it takes about a day for fermentation to get going and raise the internal temperature up around 68F, where I'll keep it until day ten or so. Well, for whatever reason, my yeast never took off. By the thirty-six hour mark, there was very little activity and the temperature was still at 64F. By day three, fermentation had started and the temperature had settled right where I wanted it. A krausen still had not formed, but I wasn't too worried. By day four I opened the chest expecting to see a thick and fluffy krausen sitting on top of the beer - a sure sign of a healthy fermentation - but instead I found a completely krausen-less beer. I raised the temp to 70F and left it to its fate. Fast forward a week. The beer never formed a krausen of any sort and the yeast did not flocculate at all. No krausen, no flocculation, and the beer looks and tastes like muddy water. However, the beer did attenuate from 1.038 to 1.010 as normal. I figure I'll give this one a week at room temp and some time in the kegerator to see if it clears up. If it doesn't, this batch is going down the drain.

Now for my second problem batch. Same story as above. My American Stout started fermention unusually slow and formed and dropped its krausen within the first thirty-six hours. The yeast is wy1272 American Ale II, which has always formed a very thick and fluffy krausen that sticks around forever. I took the carboy out of the fermentation chest to let it ferment at ambient temps (65-68F) in the hopes it might make a difference. 

In conclusion, I still don't know why both batches started out so poorly. I've never had an ale yeast not form a krausen, especially when using two top-cropping strains. I suspected yeast health might have something to do with it, but both starters fermented fast and clean, producing about 150-200ml of pure yeast slurry. Or the problem may lie with my fermentation temperatures - maybe I'm starting fermentation off too cold and shocking the yeast? Is my fermentation chest giving a false temperature? I've even considered that my sanitation practices had something to do with it... too much Starsan foam? Am I not oxygenating the wort enough?! The list goes on. Whatever the reason for my krausen-less beers, I don't have high hopes for these guys. It kills me to think that two days worth of brewing are for naught, especially if I end up dumping the batches. Frustrating stuff!

Edit: 10/29 - A bit of an update. The mild ale went down the drain. It killed me to do it, but the flavor/aroma/clarity just wasn't there. I probably could have let it sit for a month and maybe it would turn out, but I brew too much beer and I had a better use for the keg. I've stopped using my fermentation chest completely, as it seems the thing is cycling from 32F to the low 50's and back again. I'll be using the 'good-ole swamp cooler' method for the time being. The oatmeal stout, while it did not form much of a krausen, did flocculate. So there's some good news. I'll be taking a sample later today.

11/4 - Kegged the stout. Finished out at 1.016 and a bit cloudy, though the taste wasn't too bad. Maybe a little tart, though no off apparent flavors thankfully. Overall, this is not the beer I intended to brew. I had the worst stuck sparge of my life during the mash and my efficiency subsequently went down the tubes. Starting gravity was 1.050ish and with such a high final gravity, the ABV on this one is a measly 4.4%. I also ended up with a 5 gallon batch due to the stuck sparge issues, a full gallons more than I anticipated. At least, I had enough sense to go with a different bittering schedule, an oz of Fuggles for about 30 IBU. I'll let this beer condition around 45F for a week before I stick it in the kegerator for the full carbonation. 

11 comments:

  1. I've had two krausen-less beers and both were with the bad nottingham batch last year. Both beers attenuated fine, but they did taste like muddy water and the yeast never dropped out.

    You might want to hit it with a whole pack of knox gelatin and crash cool the beer for a week or two.

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  2. i just had a beamish clone with WL090 san diego super yeast crap out from 1.047-1.019. It hasnt moved from 1.019 since day three and it has been another 1.5 weeks. It started off strong and was at about 168deg and didnt drop. I transfered it on top of a WY1968 yeast cake in an effort to get 3 more points at least. we will see. It might end up a sweet stout.

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  3. Beamish. Possibly my favorite beer, purely for nostalgic reasons. I've really got to brew up another batch of it. However, I've never used super san diego yeast but I am surprised it would crap out so soon. I heard it was one beast of a yeast strain. Hopefully it works out for you.

    I kegged my mild yesterday and put it in the kegerator. If it doesn't clear in a week, I'll hit it with some gelatin to try and save it.

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  4. Well I gave the Super San Diego 10 days to get lower than 1.018 and no luck so I racked the stout on top of a yeast cake of 1968 from my invert ESB (yes following you footsteps with some modifications). Nothing after another 3 days even with heating and rousing. Plan C I added teaspoon of alpha amylase powder thinking maybe the mash was too high and it left too many unfermentables? We will see. ESB came out great though!

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  5. Let us know how the alpha amylase works out. I have some on hand, although I've never (luckily) had to use it.

    Glad to hear your ESB turned out well! I'm planning on brewing one tomorrow if I can make the invert in time.

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  6. I did an near identical mild recipe (same except used more chocolate instead of the black patent) and had a krausen-les ferment. I pitched 1968 from a fresh activator pack (less than 5 days old on brew day). The gravity sample wasn't horrible but wasn't good so a week later I transfered it to a second carboy and let it sit for almost 3 weeks. I harvested the yeast and used it in a 2 gallon split batch (which turned out fine) and then 3 other batches that all had no fermentation issues. ...and the mild- it cleared up and is awesome now. Decent head retention too. What ever caused the strange ferment didn't carry over to the finished beer or any other of the batches I fermented with that yeast. Maybe it was caused by something as stupid as not thoroughly rinsing the pbw out of the fermenter but it turned out fine in the end.

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  7. Well a week later and a bunch of rousing and the ferment is back on. I used a teaspoon of alpha amylase powder and it has a slow developing spotty krauzen on top. After a week I am down from 1.020 to 1.017 which is great. I will let it get to 1.014 if it will, then cold crash and keg. The cold should keep any further enzyme/yeast activity halted . I will report back, but so. Far so good.

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  8. I think the mild would have turned out fine if I let it age out for a while. Sorta kicking myself for dumping it. Live and learn.

    Mike, hope it continues to drop for you. My recent stout finished a bit high...

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  9. Dropped to 1.015 and I kegged it. All in all it is a decent beer and getting better. Roasty and chocolate. The mouthfeel suffered a little from the amylase, but it is better than a sweet beer. I will check my mash temp more closely for the next one and might make a "Lite" beer using the amylase for playoff season. Looks like the Pats have a chance!

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  10. I'm glad to hear the amylase worked for you in the end. I might just have to make up a 'lite' beer when the Pack gets to the playoffs. :)

    Also, I had a small glass of my oat stout today and it shows some promise. The flavor is good, albeit young, but it does have a somewhat unusual bitterness character that I am hoping will mellow out with some time.

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  11. Hi Will, Great blog by the way, dont know where you get the time but sure enjoy following your exploits. I too have a soft spot for a Mild hailing as I do from Essex area. Sorry to hear of your woes. Re fermentation temp control, here in Australia that is an important factor! Many of us are using these ... http://www.amazon.com/All-purpose-Temperature-Controller-STC-1000-sensor/dp/B00862G3TQ

    and even cheaper on Ebay...with great success. Will control temp typically within 1 degree C. I have a big old beat up 1970's fridge with a heat pad at the back and so far no worries with hot or cold ambients. Tape the sender to the side of your fermenter or keg. Cheers

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