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Old 09-15-2011, 02:40 PM   #11
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I'm not a chemist - but do pretend to be one when I use hydrometers and refractometers.

I have used a hydrometer since I started brewing and to me, the difference between the top and bottom of the meniscus probably something less than my eyes can make out unless I bother to put my glasses on.

Getting back to your original question - I just bought a refractometer a few weeks ago and have done 4 brew sessions with it. It is very handy during the mash and boil. I found myself taking readings of first runnings last runnings, pre boil during the boil etc. The abilty to take a reading without having to worry about temperature and only using a drop or two of wort is very handy indeed.

The refractometer is best used before there is alcohol involved. Once gravity has started to drop (you've made some alcohol, you have to use a calculator to correct the reading. The same 4 batches of beer are fermenting right now and I learned the stupid way that the refractometer reading has to go through a correction process once sugar has been converted to alcohol (remember when I said I'm not a chemist?). The advantage during fermentation is that you only sacrifice a few drops of beer for gravity sample instead of a cup or so to get your hydrometer floating. There is also much less sanitizing involved - only the tip of the dropper touches the beer.

I tested all for batches with hydrometer and used refractometer and the brewmate correction calculator and they all came out the same.

For me, unless there is some compelling reason to use the hydrometer, it will probably stay in it's jar from now on. I love my refractometer.

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Old 09-15-2011, 04:49 PM   #12
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The only reason I go to the hydro after fermentation is that I'm already itching to taste a few ounces to the sample is far from wasted.
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Old 09-15-2011, 09:04 PM   #13
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Originally Posted by AiredAle View Post
Based on your knowledge and approach to these questions, I have to believe you were trained as a physical chemist.
I was trained as an electrical engineer but electrical engineers do lots of measurements too and the theory of measurement is the same whether it be the gain of an antenna or the temperature of beer in the fermentor.

As noted in my previous post much of what I throw out is moot because homebrewers, by and large, don't care or don't have the resources or time to worry about such arcana but I find this subject interesting, feel the world would be a better place if people knew how to deal with measurement better than they do. I hope some readers at least find this stuff interesting.
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