testing gravity during the boil

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RobDrechsler
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Joined: Sun Jan 11, 2009 7:47 pm

testing gravity during the boil

Post by RobDrechsler »

jimmy suggested to me that I didn't boil long enough to get my gravity down to where it needed to be thus it came out thin.. so how does one go about measuring as the boil goes along, i'm guessing the hydrometer is out and would have to get a refractometer...
Beer contains just a small amount of vitamins - that's why it's necessary to drink lot of it
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Bill Lawrence
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Re: testing gravity during the boil

Post by Bill Lawrence »

Oh yeah, get thee to a homebrew store and buy a refractometer, it's so much easier. What I do is take a reading at the start of the boil (right after the hot break settles down). I know from experience where I will end up if I boil 1 1/2 hours (and I always do). I take a reading and compare that to where I want to be. Since I collect just a bit more than I need, if I need to extend the boil I do and rarely do I miss my numbers. Of course you don't want to add your bittering hops until you are an hour from knock out otherwise your IBU's will be all goofed up. By the way, especially if you use pils malt you want to go for 1 1/2 hours otherwise you'll end up with excess DMS, right? Hopefully all that was at least somewhat helpful. :D
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Jimmy Orkin
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Re: testing gravity during the boil

Post by Jimmy Orkin »

Rob, Although not boiling off enough water may have been your problem, I believe you did not start your boil with the gravity needed to have the correct gravity after the boil.

No matter, the refractometer is your friend. There are a couple of choices in refractometers, all optical or electronic. I have an all optical and electronic refractometers. I had trouble reading my all optical refractometer. The line was always fuzzy to me. It may not be a quality unit.

My electronic refractometer takes the guess work out of reading the gravity.

The all optical refractometers seem to run about $50 and the electronic one are a little over $100.

In all cases, the refractometers are made to measure room temperature samples. They are made to measure grape juice. That is why they read out in Brix. Putting hot or boiling wort on the refractometer is not a good idea. It will stress the optics. Also, hot wort in a thin layer on the refractometer will evaporate the water and make your readings look higher than they actually are.

I suggest using the plastic transfer pipettes to gather your sample and cool the wort in the bulb of the pipette in cold water. When the wort is cooled, you can take your measurement.
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RobDrechsler
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Joined: Sun Jan 11, 2009 7:47 pm

Re: testing gravity during the boil

Post by RobDrechsler »

sounds all good... and digital refractometer, haven't heard of those.. I tried using manual one and had real difficulty taking a reading... just when you think you're catching up in the equipment investment...

are there differences in the manual ones, seems there are quite a few chinese made clones out there..
Beer contains just a small amount of vitamins - that's why it's necessary to drink lot of it
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