What's my gravity?

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Jayf19

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1.058, 1.060? Or is my picture just bad.
20211219_173550.jpg
 
Hard to say from one view in a pic, but I'd say somewhere between 1.060 and 1.062. Read the bottom of the meniscus, unless your hydrometer is specifically designed/calibrated otherwise (rare).
 
Hard to say from one view in a pic, but I'd say somewhere between 1.060 and 1.062. Read the bottom of the meniscus, unless your hydrometer is specifically designed/calibrated otherwise (rare).

Thanks, I realized my picture was bad once it was too late!
 
Assuming it ferments to 1.010 then:

1.058 will give you 6.30% ABV
1.060 will give you 6.56% ABV

And even if it's 1.062 then that will be 6.80% ABV.

Will it make any bigger difference for efficiency calculations to be more accurate with what you read?
 
Assuming it ferments to 1.010 then:

1.058 will give you 6.30% ABV
1.060 will give you 6.56% ABV

And even if it's 1.062 then that will be 6.80% ABV.

Will it make any bigger difference for efficiency calculations to be more accurate with what you read?
More accurate measurements will allow more accurate calculations of efficiency. Due to the way measurement errors affect the accuracy of calculations, the least accurate measurement (error as a percentage of measured value) will have the largest effect on the error of you calculation. For example if your liquid volume measurements are +/- 4%, and all your other measurements (grain weight, grain potential, grain moisture content, SG, etc.) are all +/- 0.5%, your calculated efficiency will have an uncertainty of slightly more than +/- 4% of the calculated efficiency value. So, you want all of your measurements to be equally good. Making some extra good, doesn't help much.

Brew on :mug:
 
More accurate measurements will allow more accurate calculations of efficiency. Due to the way measurement errors affect the accuracy of calculations, the least accurate measurement (error as a percentage of measured value) will have the largest effect on the error of you calculation. For example if your liquid volume measurements are +/- 4%, and all your other measurements (grain weight, grain potential, grain moisture content, SG, etc.) are all +/- 0.5%, your calculated efficiency will have an uncertainty of slightly more than +/- 4% of the calculated efficiency value. So, you want all of your measurements to be equally good. Making some extra good, doesn't help much.

Brew on :mug:
I understand you're the official math and chemistry guru, but when figuring attenuation from OG and SG, no other measurements are used. It would be unaffected by volume - no?
 
I understand you're the official math and chemistry guru, but when figuring attenuation from OG and SG, no other measurements are used. It would be unaffected by volume - no?
Correct. I used volume in my previous post just for illustration. The math for determining the potential error is the same no matter which measurement you are looking at.

When looking at ABV calculations, you need to realize that the formula used is just an approximation, so you will have calculation uncertainty due to the formula as well as the measurement uncertainty. I haven't looked into the ABV formula enough to know just what the potential errors are.

Brew on :mug:
 
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