Hydrometer

I have read books on whiskey making, beer making, and searched the internet. They all talk about SG, BG, FG, etc. and I half way understand the gravity concept. However, I feel like a complete moron because I can not understand how to read the thing. I filled up the little plastic testtube looking thing (forget what its called) to 100 with spring water. Then I put in the hydrometer. After spilling some overflow onto the counter the water level was at the top of the plastic testube thingy and the hydrometer was floating where the water level was at 1.000 (all the way at the top). So after all this verboseness...how do I actually read this thing. KISS English only please.

Is this helpful, or do you need to know how to interpret the units that you are reading?

1)Take temp of sample
2)Place hydrometer in sample, tap it or give it a spin to knock it off the side of test jar
3)Let it rest for a couple minutes



Adjust the reading for temp (depending on what your hydrometer is set for 60 or 60 degrees)

THis is a good temp adjustment calculator.

http://hbd.org/cgi-bin/recipator/recipator/hydrometer.html

Beerthoven said:

Is this helpful, or do you need to know how to interpret the units that you are reading?

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I have no clue what you are talking about. Please tell me how to find the specific gravity of water. I think that will go a long way towards educating me. I have a tube that has a max number of 100 on it but when I fill it with water and put the hydrometer in it overflows. So what is that tube and those numbers for? And at the water level (which is at the top way above the 100 now) the hydrometer floats at 0% and 1.000. There is also another scale because this is a triple scale hydrometer. Help me understand what I'm looking at, reading isn't helping.

I think you are reading the graduations on the tube and not the graduations on the hydrometer...
The tube does not need any numbers, it's purpose is just to hold the brew or water in this case.

Revvy said:

1)Take temp of sample
2)Place hydrometer in sample, tap it or give it a spin to knock it off the side of test jar
3)Let it rest for a couple minutes

Adjust the reading for temp (depending on what your hydrometer is set for 60 or 60 degrees)

THis is a good temp adjustment calculator.

The Beer Recipator - Hydrometer Correction

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So do the numbers on the tube mean anything? Am I just suppose to fill the tube so it doesn't over flow and ignore the markings on it? And please remind me what should the specific gravity of plain ol' spring water be and what do I do to test it and make sure I know what I'm looking at. I'm completely lost. No matter how many books I've read, this somehow continues to elude me. Help!

I think you're trying to hard. It really is quite simple. You want enough liquid in your tube to allow for the hydrometer to float. Ignore your 100 on the tube (I'm guessing it's a 100ml tube).

You've already found the SG or water. You've said twice it's at 1.000. That's it. If you replace the water with fresh wort or even a finished beer you will get a different reading. I think Bobby_M has a video on how to read a hydrometer. That may be very helpful for you...

[ame=http://www.youtube.com/watch?v=xtQt7HiObuU]YouTube - Hydrometer - Brewing Beginner Series[/ame]

And by the way, if your hydrometer is reading 1.000 for water, it's doing exactly what it should. Water should read 1.000.

The numbers you want to pay attention to are the ones on the hydrometer itself, not the sample tube. The numbers on the sample tube are probably just there to show you how much you have in there. My sample tube doesn't have any numbers on it.

The specific gravity of pure water is 1.000, generally speaking. Dissolve 1 or 2 teaspoons of sugar in your water, and put the hydrometer back in. It should read higher than 1.000, say 1.030 or something like that. This means that the sugar you added has raised the density of the solution to be 3% greater than pure water.

You only need to fill your sample jar about 3/4's of the way so that when you put your hydrometer in the jar, it floats, and the beer doesn't over flow (though if it does, that's ok)

Don't concern yourself with water, if it's a new hydro, it is calibrated for distilled water already, or any of the scales on the hydrometer EXCEPT the scale in my picture, the one with .099 at the top.

If you look at that one, the Specific gravity is approx 1.072. We pronounce that "Ten seventy two"

If your tube has numbers ignore them....or note how much beer it would take that when you put the hydro in, it raises the sample almost to the top of the cylinder...then every time you fill it, you won't over flow.

kontreren said:

So do the numbers on the tube mean anything? Am I just suppose to fill the tube so it doesn't over flow and ignore the markings on it? And please remind me what should the specific gravity of plain ol' spring water be and what do I do to test it and make sure I know what I'm looking at. I'm completely lost. No matter how many books I've read, this somehow continues to elude me. Help!

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It's easy. The markings on the tube mean nothing.

1. Put the hydrometer in the tube.
2. Add water, beer, whatever, to the tube until the hydrometer floats. This should happen before the tube overflows.
3. Now look at where the hydrometer is floating.
4. See the "line" that is the surface of the water, or, in other words, where the water stops and air begins? Okay, now, look at the hydrometer, and tell me what number is at the location of the surface of the liquid. It should be 1.000 if it's 65F water.

The hydrometer works by measuring the density of the liquid; if there's more sugar in the liquid, the hydrometer floats higher, which means the surface of the liquid will be lower on the hydrometer.

Kon,
no problem!

First, don't fill the tube up all the way and don't worry about any markings on the tube, it's just there to hold the wort so that you can put the hydrometer in it. in theory, you could put the hydrometer in the kettle or fermenter directly, but that would be a PITA to read. just fill the tube up enough so the hydrometer won't bottom out (like the illustration above

second, read the markings on the hydrometer off of the scales that 1.000 - 1.010, 1.020... the other scales measure the same thing in different terms, but this is the one people refer to when they talk about OG, SG, FG, etc. I'm not sure what the markings on the tube are, it could be that tube is made for other uses and not just hydrometers. I'm guessing those are just volume measurements as in a test tube. I'd just ignore them

A tube with numbers is called a "graduated cylinder". Just in case you want to sound smart.

I have a plain cylinder. Filled with water, added hydrometer, let water spill out, removed hydrometer, then marked the new water level with a sharpie. Now I know exactly how much liquid to put in there without spilling or breaking my hydrometer.

kontreren said:

Please tell me how to find the specific gravity of water.

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Look on your keyboard for a key labeled '1'. You have now found the specific gravity of water.

My first brew I didn't have a hydrometer, I just blindly followed the instructions. It tasted like beer when I finished.
Found this site while brewing my second batch because I was going on vacation for a week right around the 9-10 day point and wasn't sure if I should bottle early or leave it sit in the fermenter. Thanks to the good people here I left it in the fermenter and bought a hydrometer while I was away. I got back home and took a reading and realized it was still fermenting. Had it not been for this site I probably would have created a case of bottle bombs and came home to a rather rancid home. Patience is key. This latest batch is probably the best beer I've ever had and I'm looking forward to future brews.

Thankx all, I finally get it. My first batch is 1 week old my second batch went in the fermenter yesterday and now I have even more questions but in an effort to conform to forum preference/policy I'll try to stick to one question per post (a difficult task for me). Since this first question is related to hydrometer I'll as it here.

NOTE: My batchs are gluten free(GF) not regular so that may make a difference.

Specific Gravity Givens:
Spring water used: 1.000 (obvious, right!)
1st batch after 1 week: 1.001 (didn't measure to start)
2nd batch after overnight: 1.003 to 1.004 (probably should have measured before pitching yeast and sealing fermenter but I forgot)

Comments:
1st batch from syrup and mostly liquid but tastes good after just one week.
2nd batch has lots of corn and rice solids, is naturally thicker but I did measure liquid w/ hydrometer.

Question(s):
Toss out any ideas why my 1st batch GF gravity is so low. I'll post my recipe/method in a separate post cause this one is long enough.

Is my 2nd batch SG in the right range generally speaking.

Toss out any ideas why my 1st batch GF gravity is so low.

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In an all-extract brew, almost all of what you put in the wort is going to be sugar that gets converted to alcohol, which means your final gravity should be pretty close to that of water. It means fermentation is almost, if not already, complete.

In a partial mash using lots of specialty grains, however, a lot of stuff in the wort is going to stick around after fermentation, so your final gravity would be somewhat higher.

bernerbits said:

In an all-extract brew, almost all of what you put in the wort is going to be sugar that gets converted to alcohol, which means your final gravity should be pretty close to that of water. It means fermentation is almost, if not already, complete.
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I thought the higher the SG the more alcohol. Did I miss the boat on that? I saw a calculation posted (FG-OG)/constant = alcohol content. I do have an alcohol thermometer but I didn't use it yet. Should have while I measured the SG. I'll follow the advice given on this site and if the SG is the same 3 days in a row I'll bottle.

kontreren said:

I thought the higher the SG the more alcohol. Did I miss the boat on that? I saw a calculation posted (FG-OG)/constant = alcohol content. I do have an alcohol thermometer but I didn't use it yet. Should have while I measured the SG. I'll follow the advice given on this site and if the SG is the same 3 days in a row I'll bottle.

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Your final alcohol by volume is 131 x (OG-FG). The rule is, the higher the OG the higher the alcohol. More specifically, the more your SG drops during fermentation, the more alcohol is present. Since sugars are denser than alcohol (a lot of weight is lost to escaping carbon dioxide), your SG will drop as fermentation occurs. Depending on how "dark" your beer is, the FG you want will be close to 1.

bernerbits said:

Your final alcohol by volume is 131 x (OG-FG). The rule is, the higher the OG the higher the alcohol. More specifically, the more your SG drops during fermentation, the more alcohol is present. Since sugars are denser than alcohol (a lot of weight is lost to escaping carbon dioxide), your SG will drop as fermentation occurs. Depending on how "dark" your beer is, the FG you want will be close to 1.

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I didn't measure the OG because I forgot but I am encouraged that it should be close to 1. My beer is NOT dark so question is how does that statement realte to me. Could you expand on what you mean. I could make many wrong conclusions from what you say 'depending on how "dark" the FG close to 1'?????

kontreren said:

I didn't measure the OG because I forgot but I am encouraged that it should be close to 1. My beer is NOT dark so question is how does that statement realte to me. Could you expand on what you mean. I could make many wrong conclusions from what you say 'depending on how "dark" the FG close to 1'?????

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Darker beers tend to have a lot more nonfermentables that contribute to the gravity of the beer. It's not uncommon to have a stout with a FG of 1.020. But with a lighter beer like yours a SG of 1.000 or very close to that usually means your fermentation is complete.

However, it's a good idea to let it age in the fermenter for a while before bottling (up to a month is fine) because that will give the yeast time to clean your beer up and make it more palatable.