Tuesday, July 12, 2011

Stuck fermentation

I went to the LHBS on Saturday, July 9th, to pick up a few items including Star San sanitizer and bottle caps. It has been two weeks since I racked the brew to the secondary fermenter so I have been thinking about getting it bottled. I stole enough of the fermenting beer from the carboy to make a gravity reading. What I learned was rather discouraging but not totally unexpected. The reading was the same as when I racked to the secondary. No further fermentation was taking place. By my calculations it is about 65% attenuated. What I have is beer, but if I bottle it like it is it would be overly sweet and a generally unimpressive beer. What I decided to do is not without risk, and may not even work at all, but I am hoping it gives me a chance to salvage this particular beer. I pitched 7 grams of Safale US-05 dry yeast directly into the carboy.

I am thinking that I will start using a nutrient blend in my next few batches as a test. If it works out I will continue to use it. Also, I want to brew the stout again, probably my next batch, using a less flocculant yeast strain than the current batch. I think I have been losing some yeast through the blow off tube, this combined with the yeast that drops out of suspension is not allowing for full attenuation. Of course, this is mostly just speculation. The proof is in the beer.

4 comments:

  1. Yeast nutrient, while not necessarily a bad thing is seldom necessary for a beer. I've brewed beers with OG as high as 1.090 without any sort of nutrient. What yeast did you use from the start? Did you make a starter? Stir plate or shaken? How much? If you used US-05, did you rehydrate? What was your fermentation temperature?

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  2. Brad, Thanks for your comments. Any suggestions are appreciated. I pitched Wyeast 1318 London Ale III in the stout. I have not had a problem before so I am trying not to over react. The US-05 was added to restart the fermentation to get to full attenuation. I know this does not alaways turn out well but it worked this time. I have been reading the book Yeast by Chris White with Jamil Zainasheff, that is where I got the idea to use the yeast nutrient. I figured it wouldn't hurt and may even help.

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  3. First, Yeast is a great book. And yeast nutrient shouldn't hurt anything or throw any off-flavors, I've just never found it necessary. If you're just pitching 1 smack pack of Wyeast Activator, You're only getting 100 billion cells at the date of manufacture. I recommend Jamil's site, mrmalty.com. You can find his yeast calculator here: http://www.mrmalty.com/calc/calc.html. With this calculator, you put in the OG of the beer, volume, and production date of the yeast (stamped on the pack). As you'll see, Jamil doesn't even offer an option for using yeast without a starter (unless it's dry --and you should still rehydrate) because there are many benefits to using a starter. You don't necessarily need a stir plate but it can cut your volume down by a large amount.

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  4. Brad,
    Thanks for your input. I have been pitching just a single smack pack. I have not made a starter yet but I am interested in doing this. What size starter is good for a 5 gallon batch? I have been focused on trying to get the equipment for all grain brewing. But perhaps I need to give more attention to fermentation. What should I look for in a good stir plate?

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