Calibrating hydrometer question

So I have a brew that appears to be finishing higher than expected, so I wanted to calibrate my hydrometer first to make sure that that's not the problem.

My question is when looking at the water line, there appears to be two different ways to read it. In 60* water, when looking at where the water line is flat and then looking at the hydrometer, it could be as much as .004 off. However, if I look at the water line at eye level, where the hydrometer touches the water, there's a little "hill" of water that comes up above the water line... like the hydrometer is drawing up a little bit of water right around it's edges. If I look at this line, the hydrometer is reading perfectly, or maybe .001 off, so there's potentially .004 difference between these two lines.

Does that description make sense? Which should I go by?

You read the high point of water where it touches the hydrometer. Hence why it was perfect when reading it that way.

I think my hydrometer came with instructions that directly addresses your question.

Of course I could be remembering it completely backwards.

BendBrewer said:

You read the high point of water where it touches the hydrometer. Hence why it was perfect when reading it that way.

I think my hydrometer came with instructions that directly addresses your question.

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Thanks! I guess I'll check my thermometer next in case I'm mashing higher than I thought.

Yep, seems like I had it backwards. Unless different hydrometers are calibrated differently.

Thanks for following up. Thermometer was perfect in boiling water, I retested the hydrometer and determined it's about .002 high in 60* water. Does this mean I should just subtract .002 from all my readings, or do I have to recalibrate it somehow? (not sure how I would be able to move the paper inside)

damdaman said:

Thanks for following up. Thermometer was perfect in boiling water, I retested the hydrometer and determined it's about .002 high in 60* water. Does this mean I should just subtract .002 from all my readings, or do I have to recalibrate it somehow? (not sure how I would be able to move the paper inside)

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Just subtract .002 from all your readings.

Yooper said:

Just subtract .002 from all your readings.

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Thanks again... happens to be your oatmeal stout that I brewed on Friday that I'm concerned about. Yeast appear to be fully dormant, temp has dropped to 61*, and even with the .002 adjustment I'm at 1.020. I did dough-in too hot because I didn't account for the extra water in the mash when calculating strike temp, but I added ice and got it down to 157 in about 5 minutes (finished 155 after 60 mins).

I realize it could still drop a couple points but given the temp range for the yeast and what I've observed I'm not optimistic.

I believe hydrometers are calibrated to be perfect at 59 deg. F, so there are lookup tables on what to ADD to your readings for the temp. of the room when the reading was taken.

I hope I didn't just go off topic.

damdaman said:

Thanks again... happens to be your oatmeal stout that I brewed on Friday that I'm concerned about. Yeast appear to be fully dormant, temp has dropped to 61*, and even with the .002 adjustment I'm at 1.020. I did dough-in too hot because I didn't account for the extra water in the mash when calculating strike temp, but I added ice and got it down to 157 in about 5 minutes (finished 155 after 60 mins).

I realize it could still drop a couple points but given the temp range for the yeast and what I've observed I'm not optimistic.

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1.020 sounds fine, actually. With that recipe, and mashing it at 157, it's done. Just give it some time to "clean up" some flavors and it'll be fine.

Yooper said:

1.020 sounds fine, actually. With that recipe, and mashing it at 157, it's done. Just give it some time to "clean up" some flavors and it'll be fine.

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Will do... the sample tasted delicious.

damdaman said:

Will do... the sample tasted delicious.

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Glad to hear it! As I said in the thread, I was really disappointed at first when I sampled it as it came out of the fermenter. I thought it was harsh and roasty- the things I was trying to avoid! I wanted the coffee/roasty flavors but not that harsh/burnt/acrid flavor sometimes dry stouts have. So I was disappointed at the sample. But after a couple of weeks, it turned out to be a real treat!

Bob just mentioned yesterday that he bought steel cut oats at the store for me, so "you can make that good beer again!". I didn't have the heart to tell him that I usually use flaked oats, so I can see me doing a cereal mash and making this again as soon as I can.