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hialtitude 09-10-2007 03:40 PM

Calculating Efficiency
 
I have read Palmers take on calculating your mash efficiency and am left with a question. When I take a hydrometer reading of the wort collected pre-boil, do I need to convert that number based on temperature? I measured my OG to be 1.032 pre-boil for six gallons at approximately 150 degrees F. Thanks!

Bobby_M 09-10-2007 03:44 PM

It doesn't matter what the purpose of the reading is, you must always compensate for the sample temp. Many online calculators available... I'm too lazy to search and link.

hialtitude 09-10-2007 03:46 PM

That's what I figured, but wasn't sure based on the way Palmer discussed it. There was no direct mention of compensating for temp and I wanted to be positive.

bradsul 09-10-2007 03:57 PM

Quote:

Originally Posted by hialtitude
That's what I figured, but wasn't sure based on the way Palmer discussed it. There was no direct mention of compensating for temp and I wanted to be positive.

Compensating for temperature is a necessary step when using the hydrometer for any reading, I imagine he thought it was unnecessary to mention.

heinz57 09-10-2007 04:08 PM

Quote:

Originally Posted by hialtitude
There was no direct mention of compensating for temp and I wanted to be positive.

Check out Appendix A labeled "Using Hydrometers." There he discusses the need to compensate the temperature and lists a table of the necessary delta T's.

Hope this helps.

WOP31 09-10-2007 04:19 PM

I don't know about anyone else i would be a little worried about dropping my hydrometer in 150deg wort. I usualy cool my wort before taking a reading, at least closer to 70. I guess that I would just worry about the hydrometer cracking or something from the sudden temp change.

Cheers

bradsul 09-10-2007 05:52 PM

Quote:

Originally Posted by wop31
I don't know about anyone else i would be a little worried about dropping my hydrometer in 150deg wort. I usualy cool my wort before taking a reading, at least closer to 70. I guess that I would just worry about the hydrometer cracking or something from the sudden temp change.

I believe they are also less accurate the farther from the calibration temperature you get (though don't quote me on that). That said I always cool to about 70F as well, though I rarely take a reading at the end of sparging anymore.


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