Refractometer and Hydrometer - Can you see my neck ?

Thu Apr 12, 2007 1:43 pm

Apparently, I have somehow managed to suspend Mr. Newton’s Universal Law of Gravitation and seriously call into question Mr. Einstein’s General Relativity theory right here in my own little home brewery.

After 5 days of extremely harmonious fermentation of an ESB that I whipped up, I thought I might check the gravity and see just how far it had progressed. I really wanted to taste this beer, so I went ahead and filled up my hydrometer tube. I grabbed a few drops and put them on the Refractometer (an RHB-32ATC) and it measured 6.6 brix. Then, I dropped my hydrometer in and to my surprise it measured 3.5 brix. (It measures brix and SG.) the hydrometer read 1.014.

I did both measurements from the exact same sample, at the same temp (70 degrees F) and repeated them several times. I double checked my refractometer calibration with RO water so I know it is reading correctly. Also, I used 2 different hydrometers to make sure that they were not the problem.

Finally, I tasted this beer and it’s great. I really don’t want it to go any further so I’m just going to keg it up and drink it.

Any thoughts on what the hell is going on with my instruments? What am I missing here? Have I somehow altered the physical universe or do I just have my head in my ass?

Rease
Build a Man a Fire, he'll be warm for a day. Set a Man on Fire, and he'll be warm for the rest of his life.
- Anon
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ReaseB
 
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Thu Apr 12, 2007 2:45 pm

Your missing something Rease. You need the original gravity AND the Refractometer reading for the Rrefractometer to give you a gravity reading during or after fermentation. You cannot go by just the Refractometer reading alone. There is a complicated math formula or you can use brewing software like Promash. It has to do with the alcohol affecting the readings. The hydrometer is affected by the alcohol giving you the Apparent Degree of Fermentation (ADF). The Refractometer reading is closer to the Real Degree of Fermentation (RFD) which is the actual sugars left in the beer. Check out http://www.byo.com/feature/1132.html for more info from Colin Kaminski who has been on TBN.
Dan
ENJOY YER BEER and let them that don't want none have memories of not havin' any!
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diver
 
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Thu Apr 12, 2007 6:53 pm

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BrotherhoodBrew
 
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Fri Apr 13, 2007 12:31 am

SHAAAAZAAAAMMM !!! That all makes sense. Post fermentation, we are not measuring sugar in water, we're measuring sugar in alchohol/water etc.,

See, thats why I love this sport. PM me and I'll send you a bottle of ESB.

Great thanks!

Rease
Build a Man a Fire, he'll be warm for a day. Set a Man on Fire, and he'll be warm for the rest of his life.
- Anon
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ReaseB
 
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Joined: Sun Mar 05, 2006 11:36 am
Location: Bozeman, MT

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