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Old 04-03-2013, 03:24 AM   #1
zrule
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I received a refractometer as a gift but the reading I get is off by quite a bit from a hydrometer. They both read 1.000 for water but the refractometer reads 1.032 and the hydrometer reads 1.020. at end of fermentation. What gives?

 
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Old 04-03-2013, 03:52 AM   #2
laytoni
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Question for anyone on converting kegs to brew pots. Is there a preferred keg material. Aluminum vs an old stainless. The old stainless ones are harder to come by!

 
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Old 04-03-2013, 04:01 AM   #3
Felixio
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Quote:
Originally Posted by zrule View Post
I received a refractometer as a gift but the reading I get is off by quite a bit from a hydrometer. They both read 1.000 for water but the refractometer reads 1.032 and the hydrometer reads 1.020. at end of fermentation. What gives?
Refractometers have been known to be off when the material being measured contains alcohol. There are a number of spread sheets online for figuring out true gravity given the measured gravity of the beer. Of course, these have also been known to be inaccurate. In short, hydrometers are better when you're dealing with beer/wine, but refactometers are quick and accurate when dealing with wort or grapes.

 
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Old 04-03-2013, 04:07 AM   #4
Felixio
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Quote:
Originally Posted by laytoni View Post
Question for anyone on converting kegs to brew pots. Is there a preferred keg material. Aluminum vs an old stainless. The old stainless ones are harder to come by!
So, this should be on another thread.... Anyway, there are a lot of opinions out there on this on. The reason why kegs are such a common item to begin with is because they are made of stainless steel, easy to find, hold 15 gallons (and thus are perfect for 10 gallon batches), have a good height to width ratio for low liquid loss during boil, and a cheap when compared to the cost of buying a new pot of the same material.

As for using aluminum vs stainless, well, there is a sticky that is basically "in defense of aluminum". You know all of the reasons to use stainless, so here you go.
http://www.homebrewtalk.com/f11/faq-...kettles-49449/

 
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Old 04-03-2013, 04:11 AM   #5
iaefebs
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this thread got derailed.

 
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Old 04-03-2013, 04:33 AM   #6
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Wow..back on track.. I always use my Hydrometer to measure during fermentation and for my FG. Only use the refractometer for Pre-boil, Mash+ Sparge runnings, and post boil..
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Old 04-03-2013, 04:45 AM   #7
branCHEs
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Quote:
Originally Posted by zrule
I received a refractometer as a gift but the reading I get is off by quite a bit from a hydrometer. They both read 1.000 for water but the refractometer reads 1.032 and the hydrometer reads 1.020. at end of fermentation. What gives?
Refractometers measure gravity by reading how much the light bends through the given liquid. When alcohol is present in the liquid, the light bends differently giving the user a skewed gravity reading.

My suggestion:

1) Use your refractometer to measure OG (there is no alcohol present so you should have an accurate reading if it is calibrated properly). Record this number.

2) Use your refractometer to check the gravity during the end of fermentation. Although this will not give you an accurate reading of the actual gravity (because alcohol present), it will give you a consistent reading. Once the reading is the same for three days in a row you know that fermentation has ended and it is time to bottle/keg.

3) On bottle/keg day, take a final reading of your beer using hydrometer (becAuse alcohol is present now). Record this number. Use the number from step 1 and step 3 to find your ABV.

In short, use the refractometer to measure the OG. Use the refractometer to determine when fermentation has stopped. And use a hydrometer to measure the FG.

The reason not to use the refractometer for measuring the FG is because the charts online have been proven again and again to be inaccurate (last time i checked, however things could have changed since then).

 
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Old 04-03-2013, 04:51 AM   #8
iaefebs
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I use a refractometer only throughout the whole process. If you have a dual scale refractometer it is causing confusion. Those things should be thrown away.

 
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Old 04-03-2013, 04:51 AM   #9
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I also like to use the hydrometer to taste a sample, to see if there are any other issues..
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Old 04-03-2013, 04:54 AM   #10
iaefebs
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Quote:
Originally Posted by branCHEs View Post
Refractometers measure gravity by reading how much the light bends through the given liquid. When alcohol is present in the liquid, the light bends differently giving the user a skewed gravity reading.

My suggestion:

1) Use your refractometer to measure OG (there is no alcohol present so you should have an accurate reading if it is calibrated properly). Record this number.

2) Use your refractometer to check the gravity during the end of fermentation. Although this will not give you an accurate reading of the actual gravity (because alcohol present), it will give you a consistent reading. Once the reading is the same for three days in a row you know that fermentation has ended and it is time to bottle/keg.

3) On bottle/keg day, take a final reading of your beer using hydrometer (becAuse alcohol is present now). Record this number. Use the number from step 1 and step 3 to find your ABV.

In short, use the refractometer to measure the OG. Use the refractometer to determine when fermentation has stopped. And use a hydrometer to measure the FG.

The reason not to use the refractometer for measuring the FG is because the charts online have been proven again and again to be inaccurate (last time i checked, however things could have changed since then).
I see more error from people reading a hydrometer. Always viewing the meniscus from whatever angle gets the results they are hoping to see.

 
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