Forgot the temperature correction (1st brew)

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Forgot the temperature correction (1st brew)

Postby mrocco » Sat May 12, 2007 9:30 am

Having a good bit of experience with winemaking, decided to go straight into all-grain (pale ale) with my first brewing attempt. Everything worked out fairly well. However, during sparging, checked the SG several times to see when it got below 1.010. I measured 1.008, so I stopped. Forgetting to correct for temperature (approx. 170 deg F), which calculates to about 1.033 I ended up with: 1.) 4 gal instead of 5, 2.) 6.9% abv instead of 5.3, 3.) 38 IBU instead of 30, and 4.) 12 SRM instead of 10. Oh well,live and learn. Not a disaster, but not quite what I was looking for, esp the 6.9 % abv. Environment was a little warm (ambient 74F), so the temp inside the fermenter was approaching 80F--fermentation down to 1.008 in two days (from 1.061)--kreusen dropped. Racked to secondary (been there 5 days). Sample at racking tasted great!
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Re: Forgot the temperature correction (1st brew)

Postby billvelek » Sat May 12, 2007 10:36 am

mrocco wrote:Snip ... Environment was a little warm (ambient 74F), so the temp inside the fermenter was approaching 80F ... snip

I don't know how it is with wine, but fermenting beer at that temp will definitely create esters (fruity flavors, usually unwanted in beer), and even worse, fusel alcohols which can cause a splitting headache with as little as just a couple of beers, and make any hangovers even worse. Whenever you ferment and ambient temp is that high, put your fermenter in a shallow container of water of some sort -- a tub or tray or something to hold just a few inches of water -- and then wrap a towel around the fermenter, allowing the bottom of the towel to sit in the water. The water will wick up the towel and then evaporate, helping to keep the fermenter a couple or few degrees cooler. With temps as high as you had, I would add a small desk fan to blow air on the towel to speed the process, and maybe even dump a tray of ice cubes into the water occasionally. If the towel can't wick the water fast enough, use a ladle to dip the water from the container over the towel whenever it begins to dry. Most of your fermentation and heat will occur during the first day or two during high krauesen, so in warmer weather you might plan on brewing at the beginning of the weekend or your days off if you work so that you can help pay attention to it as per above. ... Or ... lower the thermostat on your air conditioning for a couple of days. Personally, I try not to let my ales ever get past 72F; I've read that the ideal temp is generally between 65F and 70F, but my wife won't let me keep it that cold in the house. :mrgreen:

I hope your first brew comes out to your satisfaction, and that it doesn't cause headaches; homebrewers can live with fruity esters -- the beer is at least drinkable -- especially when just learning.

Good luck, and welcome to our forums.

Cheers.

Bill Velek
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Postby mrocco » Sat May 12, 2007 11:06 am

I actually did use the wet t-shirt method of cooling after I noticed that the temp was getting high. As I stated earlier, the fermentation only took 2 days, so there wasn't a lot of reaction time. The temp didn't get that high until day 2.

Looking at my basement I realized that, for a few bucks, I can use some pvc pipe to pump cold air directly from the ductwork coming out of the air conditioner into the cupboard where my fermenter sits. This ought to lower the ambient temps into the mid-60's in that small, confined space. With the addition of a damper in the pipe, I'll be able to shut it on/off.
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adjust gravity prior to boil

Postby slothrob » Sat May 12, 2007 2:43 pm

The other thing to realize is that the amount of sugars that you had in your 4 gallons at 6.9% abv could have been diluted, preferably prior to the boil, to make 5.2 gal. at your target of 5.3%.

I always take a gravity reading just prior to the boil, knowing how much I will evaporate away and so what my gravity needs to be prior to boil to hit my desired gravity post boil. This allows me to correct the volume or correct the hop additions to make something closer to the beer I originally intended to make.
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Postby mrocco » Sat May 12, 2007 10:22 pm

Yeah, I figured out the temperature correction problem too late. Didn't want to add any water after I started the fermentation. Most people don't seem to think that's a good idea.
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