Hydrometer Question

After finishing the boil and cooling the sample my buddy received a reading of 1.040 on his hydrometer. I have been getting low OG readings and decided to use my hydrometer. Using the same sample I stuck my hydrometer in and received a 1.030 reading. I then dumped the sample and added tap water to the tube. Both hydrometers then read 1.000. What's the deal?

Did you both correct for temperature? It's possible that your two hydrometers are calibrated at different temperatures.

Brian

Didn't think of that. I'll check it when I get home. We did get them from two different places. Thanks!

Was this from an extract recipe or all-grain? What was your recipe?

What I am getting at is maybe you guys didn't hit your numbers (i.e. not enough extract or didn't complete mashing).

Even if the hydrometers had different calibration temps, 60 and 68 are all I've ever seen, It wouldn't make a .10 point difference, only 1 or 2.

FensterBos said:

Was this from an extract recipe or all-grain? What was your recipe?

What I am getting at is maybe you guys didn't hit your numbers (i.e. not enough extract or didn't complete mashing).

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He measured the same sample with 2 different hydrometers and got 2 totally different readings, not sure why it would matter if it was all grain or extract.

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Not sure why this would occur but possibly the first reading was taken why there was still cold break and other particles in suspension sticking to the hydrometer causing it to float higher giving a reading of 40 pts, the 2nd reading was taken later after the sample had time to settle giving a more accurate reading. 30 pts is pretty low so if this were the case you'd have far worse problems.

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If you are doing extract brew and adding water at the end of the boil to make the "5 gallon mark" then it is possible that you have not stirred the wort long enough. When you combine liquids of different gravities they tend not want to mix very easily so you should mix (slowly) but thoroughly.

Just an idea!

If I'm reading the OP correctly, he was measuring the same sample with two different hydrometers, so it doesn't sound like a topping off problem (my first thought until I reread it). I know my hydrometer likes to hang on the side of the tube and screw with the results, but if this has been a recurring problem that's not as likely. I know CO2 bubbles can lift a hydrometer after fermentation, so maybe bubbles of some sort if the wort got mixed up? Would think cold break would pull it down rather than lift it up.

What you might want to do is either find a third hydrometer/refractometer and compare it to your results. You could also take some sugar and dissolve it in some water to a known gravity, then measure it with both of your hydrometers and figure out which is correct.

It was an AHS Partial Mash Harp clone. The OG AHS gave was 1.051 and we of course didn't get anywhere near that, but we are working on that part. We did cool the wort after the boil and then top off with water to create the 5 gals. After mixing (funneling the wort into the carboy) the wort we then siphoned a sample into the hydrometer tube. We placed his hydrometer in the tube and spun it around. When it stopped it was 1.040. I then took his out and placed mine in the same sample, spun it, and it read 1.030. I'll have to measure a sugar water mix for testing purposes.

The previous PM I did was an AHS Bock. It was supposed to be 1.045 OG and I recorded 1.042 OG. It was supposed to be 1.012 FG and I recorded 1.002 FG. I thought 1.002 was a bit odd and therefore assumed something was off.

Thanks for the help. I'll also pick up a 3rd hydrometer next time I order.

I think I misunderstood your question when I referenced if you were using extract or partial/all-grain.

As the other guys mentioned, the two hydrometers shouldn't be so inaccurate. Is there a chance that one of them is damaged? From my understanding hydrometers do not go bad; once they are calibrated they are pretty consistent. If you have a lhbs I would bring in the hydrometer.