Read my hydrometer - PLZ

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brewswithshoes

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I have struggled with reading a hydrometer correctly since starting this hobby, and i'm sure there are even varying opinions on how to read it correctly. I know in the end it really doesn't matter as long as i use the same reading indicator at beginning & end, but unfortunately i was raised by an extreme perfectionist and i need to know for sure.:confused:

Please take a look at the pic if you will and tell me what the reading is..... (i'm reading it as 1.051)
IMG_0360.jpeg
 

VikeMan

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Looks like about 1.055 to me. Always read at the bottom of the meniscus. But, I wouldn't recommend having the jar overflow like that. It makes it hard to read.


I know in the end it really doesn't matter as long as i use the same reading indicator at beginning & end, but unfortunately i was raised by an extreme perfectionist and i need to know for sure.:confused:
While it may not matter for ABV calculations, it does matter for apparent attenuation calculations and efficiency calculations.
 
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brewswithshoes

brewswithshoes

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thank you for readings. so i've heard the meniscus mentioned a lot in other interpretations of reading volume. when i look at that pic, i see a meniscus that goes up in the middle onto the hydrometer, so reading from the meniscus is where i interpreted the 1.051 (maybe 1.052).

is that not correct and the meniscus is really the inverse of that as it "attaches to the cylinder" instead of attaches to the hydrometer?
 
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brewswithshoes

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Also, i know it's not scientific at all but my Tilt came in at 1.053 (i don't really use my Tilt readings for anything other than to watch the gravity drop for things like when to dry hop, diacetyl rest, etc.)

One other data point - my refractometer read 1.050 from a sample pulled from that cylinder as well.o_O

you can see how this could drive me mad with the inconsistencies in source points.
 

VikeMan

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The meniscus is that whole upper curved surface. It has a top and a bottom, and the right place to read it is at the bottom. But it wouldn't normally be where it attaches to the cylinder either...it would be the bottom of the "trough" formed as a result of the wort clinging high on both the hydrometer and the cylinder. It's not like that in your pic, because your jar is filled too high
 
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VikeMan

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One other data point - my refractometer read 1.050 from a sample pulled from that cylinder as well.o_O
Did you read it in brix and convert to SG using a refractometer calculator that uses a wort correction factor? And had the refractometer been calibrated? I'm guessing it wasn't calibrated, because with correction that gravity would have been even lower.

Also, it's a good idea to check your hydrometer in plain water at whatever temperature it's manufactured for.
 

hotbeer

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I just draw in my head an imaginary line at the surface level and ignore the meniscus going up the side of the hydrometer. I see at least 1.055 too. I only fill my tube with enough beer to float the hydrometer off the bottom. To me it's easier to read if both meniscus' are going the same way.

FYI, Some types of solutions the meniscus goes the other way down into the solution. Probably never see that with wort or beer.
 

day_trippr

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My hydro basically implies "ignore any meniscus effect", so I would say 1.055...

Cheers!
 

hotbeer

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You ignore the meniscus. Many say read from the bottom of the meniscus, but then that gets confusing if you happen to have a fluid in there that has an inverted meniscus.


It's the actual surface level of the fluid you want to read.
 

Dgallo

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If that was my reading, I’d write it down as 1.055 and call it a day
 

hotbeer

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That'll never happen with beer. I'm trying to think of something besides mercury that would be inverted.
No I don't think it will happen with beer either. Especially with a glass hydrometer.

I've seen it with other things... not just mercury. Don't remember what. And I wasn't using a hydrometer or even measuring. Typically I remember it being just an odd thing I noticed when putting something into the liquid. Maybe like a stir rod.

I think it has to do with the affinity of the solution to the material of whatever it comes in contact with along with surface tension perhaps. But that was long ago.
 

superiorsat

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Yeah, I'm gonna rock the boat here. I read at the top of the meniscus. For starters it is the only place you can clearly see the level without looking through wort (sometimes jet black wort) to see a mark that you have to imaging being level with the wort outside the meniscus. On a dark stout you would be totally guessing. Say for example 1.055 to 1.014 is 5.35% abv with your 4 point higher number looking through meniscus. Then 1.051 to 1.010 would also be 5.35% abv with the numbers being say 4 points less since you didn't look through the meniscus. It is the same either way. I also like to have the wort to the top of the tube so I can blow off any bubbles and get a straight on view with my old eyes and I also have to camera shot it to tell some times.
 

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VikeMan

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Say for example 1.055 to 1.014 is 5.35% abv with your 4 point higher number looking through meniscus. Then 1.051 to 1.010 would also be 5.35% abv with the numbers being say 4 points less since you didn't look through the meniscus.
Yes, it's already been stated that the ABV answer will be the same. And if you don't care about calculating mash efficiency or attenuation, that's fine.
 

IslandLizard

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1.056!

Properly read at the bottom of the meniscus.
I intentionally skipped all the other posts.
OK, this was bugging me. I'm hereby rescinding my initial observation!

The scale distortion (optical refraction) inside the meniscus throws off the reading.
Here's a more accurate representation. The blue (vertical) lines are equal length:

Hydrometer Reading 1.055_Diagram.jpg


1.055 it is!
Perhaps a tiny tad less, 1.0548 or 1.0549.
Placing the line on the surface (the bottom of the meniscus) is a bit arbitrary, I used my best judgement.
 

Birrofilo

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Read the instructions of the manufacturer. My hydrometer's instructions specifically say to read on top of the meniscus.

If you lost the instructions, just measure pure distilled water at 20°C (again, this is true if the hydrometer is calibrated at 20°C. Some are calibrated at 15°C) and see whether 1,000 is read at the bottom of the meniscus or at the top of the meniscus.
 

VikeMan

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If you lost the instructions, just measure pure distilled water at 20°C (again, this is true if the hydrometer is calibrated at 20°C. Some are calibrated at 15°C) and see whether 1,000 is read at the bottom of the meniscus or at the top of the meniscus.
While distilled water would technically be best, tap water (at the correct temperature) is fine too. In order to skew gravity up by one point, the water would have to contain approx 2600 mg/l Total Dissolved Solids. With real life tap water, I think the difference would be undetectable by eye with a normal brewing hydrometer.
 

bracconiere

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honestly, i don't get much meniscus when i just drop the hydro in my 15 gallon brew kettle to check gravity......
 

VikeMan

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honestly, i don't get much meniscus when i just drop the hydro in my 15 gallon brew kettle to check gravity......
They look somewhat smaller when you're not seeing them right at at eye level.
 

bracconiere

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ahhh, i guess this thread has given me something new to think about besides just getting the damn things to show me the SG..... :mug:


edit: meniscus, minutia.....
 
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brewswithshoes

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OK, this was bugging me. I'm rescinding it.

The scale distortion (optical refraction) inside the meniscus throws off the reading.
Here's a more accurate representation. The blue (vertical) lines are equal length:

View attachment 725384

1.055 it is!
Perhaps a tiny tad less, 1.0548 or 1.0549.
Placing the line on the surface is a bit arbitrary, I used my best judgement.
This was an incredibly detailed and produced post. Thank you @IslandLizard
 

hotbeer

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Yeah, I'm gonna rock the boat here. I read at the top of the meniscus. For starters it is the only place you can clearly see the level without looking through wort (sometimes jet black wort) to see a mark that you have to imaging being level with the wort outside the meniscus. On a dark stout you would be totally guessing. Say for example 1.055 to 1.014 is 5.35% abv with your 4 point higher number looking through meniscus. Then 1.051 to 1.010 would also be 5.35% abv with the numbers being say 4 points less since you didn't look through the meniscus. It is the same either way. I also like to have the wort to the top of the tube so I can blow off any bubbles and get a straight on view with my old eyes and I also have to camera shot it to tell some times.
Yeah, a lot of other forums I go to for other things we dwell too much on being accurate to the nth decimal place when it really doesn't add much error to the actual result.

As a noob, it's nice to know the same happens here. Leaves so much open for discussion and posturing.
 

Birrofilo

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Say for example 1.055 to 1.014 is 5.35% abv with your 4 point higher number looking through meniscus. Then 1.051 to 1.010 would also be 5.35% abv with the numbers being say 4 points less since you didn't look through the meniscus. It is the same either way.
The reason why people take density measurements is not limited to ABV estimation. I as an example take intermediate readings with a refractometer and I "confirm" the final reading with a hydrometer.

Knowing where to make the reading is important or one has too different answers to the same question by two different instruments. 4 points apart is not acceptable in my mind. I think that good process is related to good measurements, in the long run it makes the understanding of the process better, and the beer better too (or nearer to expectation).

In the two cases, the apparent attenuation is 74,5% and 80%. Two quite different attenuations. One doesn't come to good knowledge of the process with sloppy measurements. That doesn't mean that measuring exactly leads automatically to good beer, but it's one of the things that the "compleat" homebrewer cares about.

The datum itself, of 5,35% ABV, is interesting only for the process knowledge's sake. 4,9 or 5,5%, it's always beer ;)
 
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IslandLizard

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I do hope everyone understands that however you read a hydrometer, bottom or top of the meniscus, or anywhere else, you must read exactly the same way when calibrating, while noting any deviation from the expected "null" point. Then apply that correction to every reading from there on with that same amount.

For example my hydrometer reads 1.002 at the bottom of the meniscus in distilled water at its calibration temp of 60F. So every reading should also be taken at the bottom of the meniscus, at 60F, and be corrected by -2 gravity points.
E.g., a reading at the bottom the meniscus (@60F) of 1.056 represents a (real) gravity of 1.056 - 0.002 = 1.054.
 
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brewswithshoes

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On my hydrometer that would be 1.051.
The directions specify the top. So test it in water and see what it does.
View attachment 725476
Thank you for this. This is exactly where my thinking came from as this exact info was on my first hydrometer many years (hydros) ago and the basis for why I’ve been reading it like that since. My latest hydro has no info other than the graduation lines, so maybe it’s not the same.

I guess the main thing I’m taking from hydro readings is that’s it is specific to how that specific hydro was designed to be used/read.

now to go figure out how to calibrate all my other tools to all be in sync.

maybe I just throw everything away and jump to an AntonParr EasyDens.:mischievous:
 

VikeMan

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It actually boggles my mind (a little) that there are some hydrometers calibrated/coming with instructions to read the top. I'm pretty sure that the height of the meniscus varies a little with wort properties. If so, that would mean those hydrometers are intended to measure an approximation. Maybe it's not big enough to make much difference. But it offends my delicate scientific sensibilities. I think I need a safe space.
 
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