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orcus332 09-29-2011 09:53 PM

hydrometer calibration
 
Hey guys,
I'm trying to get my hydrometer (calibrated at 60F) dialed in here. At 70F with distilled water, it reads 0.096. I put this into beersmith's calibration tool and it says the gravity is truly 0.096.
The beer I just brewed had an OG of 1.064 @ 80F. Corrected using beersmith, this would be 1.066.

Am i correct to assume that since my hydrometer is reading about 4 points low, that the actual OG would be 1.070?

Also, is there anyway to manipulate beersmith so that it takes into consideration that my hydrometer reads 4 points low?

truebe 09-29-2011 11:03 PM

are you reading from the correct side of the meniscus? 4 points seems like a pretty big calibration error for them to make.

fuhmon 09-29-2011 11:14 PM

ya read the line under the wort level.
http://www.lumcon.edu/education/studentdatabase/hydrometer.asp

truebe 09-29-2011 11:37 PM

some hydrometers want you to read at the top of the meniscus. do you still have the instructions that came with it?

But i guess that doesnt help much in this case since reading from the top instead of the bottom would move you farther away from 1.000

Yooper 09-29-2011 11:40 PM

Quote:

Originally Posted by orcus332 (Post 3342144)
Hey guys,
I'm trying to get my hydrometer (calibrated at 60F) dialed in here. At 70F with distilled water, it reads 0.096. I put this into beersmith's calibration tool and it says the gravity is truly 0.096.

I think you mean .996. But what is this about Beersmith's calibration tool? I mean, if you put the hydrometer at 60 degrees with distilled water and it read .996 that's fine. But it's "corrected" to .997 if you read it at 70 degrees. Either way, that number you have from Beersmith is wrong!

ajdelange 09-29-2011 11:53 PM

What a hydrometer reads depends on
1. The weight of the instrument
2. The diameter of the stem
3. The surface tension of the liquid
4. The temperature
5. The "offset" which you can think of as the amount the paper on which the scale is printed is mispositioned inside the stem.

If your instrument reads 0.004 low in distilled water and assuming it is calibrated for water that's an offset. Apply that to any reading before you do any correction for temperature.

orcus332 09-30-2011 01:03 AM

Good catch yooper, yeah i meant 0.996. And yeah, i'm not sure where i got a corrected value of 0.996 the first time, you're right, it was 0.997.

Here's a pic of the instructions that show the reading should be taken from the top of the meniscus:
http://farm7.static.flickr.com/6158/...7a534022_d.jpg

Also, i just re-read my hydrometer. Got 0.998 @ 62F so a bit closer to 1.

Is there any way to have beersmith automatically add 2 points to all my readings since my hydrometer reads 2 points low, or is that just something I'll have to do manually? I have version 1.4 btw


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