help reading hydrometer/abv

Hello! New brewer here. I've had 2 good (well, drinkable) batches so far, have a 3rd in the secondary and planning on a couple more in the coming weeks. My question is how to accurately read the hydrometer/gravity/abv levels. The first few batches, I wasn't really paying attention to all the technical aspects (gravity levels, etc.). I just wanted to make beer and drink it. Now, I'm very interested in everything beer and have been doing a ton of reading on it.

I notice on the hydrometer the gravity levels, sugar levels, and ABV levels. The current batch I have sitting in secondary, I came pretty close to hitting the final gravity reading. I think I was .02 off. The recipe states that the ABV for it should be about 6.5%. However, if I was .02 off from the final gravity reading, the ABV was around 4-5% (can't remember the exact number), how is it suppose to be at 6.5% How is ABV measured exactly?

Thanks for any advice!

The only scale we use on a triple scale hydromter in homebrewing is the soecific gravity (sg) scale, the other two are used in making whiskey if I recall, and don't really work for beer.

TO determine the abv, you take an original gravity reading, and a final gravity reading and apply this formula, OG - Fg x 131.

kaizer said:

I came pretty close to hitting the final gravity reading. I think I was .02 off. The recipe states that the ABV for it should be about 6.5%. However, if I was .02 off from the final gravity reading, the ABV was around 4-5% (can't remember the exact number), how is it suppose to be at 6.5% How is ABV measured exactly?

Thanks for any advice!

Click to expand...

If you "came pretty close" are you sure you weren't .002 off instead of .02?

a few things i have learned about hydrometers:

1. the potential alcohol scale of my hydrometer never seems to agree with online calculators when attempting to determine ABV

2. hydrometers are calibrated at 60 degrees, so my 70 degree readings need to be adjusted a little

3. you are supposed to read the top of the meniscus if you see any curvature on the surface of your liquid

4. satellite sample batches are a great way of preventing wasted beer

5. spin your hydrometer or tilt your sample tube if the hydrometer wont stop clinging to the inside of the tube

SoonerDoc said:

If you "came pretty close" are you sure you weren't .002 off instead of .02?

Click to expand...

yes, sorry forgot to add a 0. i'm going off of memory. i'm still new to the whole reading stuff.

can i do a gravity reading after its done in the secondary or before bottling (after adding priming sugar) just to see what it will be at?

thanks again!

Dogphish said:

a few things i have learned about hydrometers:

1. the potential alcohol scale of my hydrometer never seems to agree with online calculators when attempting to determine ABV

2. hydrometers are calibrated at 60 degrees, so my 70 degree readings need to be adjusted a little

3. you are supposed to read the top of the meniscus if you see any curvature on the surface of your liquid

4. satellite sample batches are a great way of preventing wasted beer

5. spin your hydrometer or tilt your sample tube if the hydrometer wont stop clinging to the inside of the tube

Click to expand...

On Item3, I think you supposed to read the "bottom" of the meniscus, like below.

I am just getting started, I was messing with my hydrometer. To test it out I just took a look at some water and some store bought beer. Helped show where I should be looking, and to make sure my hydro was calibrated.

kaizer said:

yes, sorry forgot to add a 0. i'm going off of memory. i'm still new to the whole reading stuff.

can i do a gravity reading after its done in the secondary or before bottling (after adding priming sugar) just to see what it will be at?

thanks again!

Click to expand...

If that's the case, your alcohol content won't be very far off.

You can do gravity readings whenever you want. It's helpful to see what's going on. However, be careful. You can introduce bugs any time you mess with your beer, so I wouldn't check too often. Remember to sanitize everything.
Check FG at bottling before adding the priming sugar. You want to check before bottling anyway to avoid bottle bombs. Make sure it has finished fermenting.

Thanks! I'm pretty sure my measurements weren't based off of 60 degree temperatures either. I think its more around 70 or so. What adjustments are you suppose to make?

my hydrometer says to read the top of the meniscus, so i guess that varies from brand to brand, or that diagram above is incorrect.

i own a Alla France brand Wine and Beer Hydrometer and it says "take reading as shown on the diagram" then shows a picture of someone reading the top of the water line clinging to the hydrometer, and says "reading above meniscus".