• Please visit and share your knowledge at our sister communities:
  • If you have not, please join our official Homebrewing Facebook Group!

    Homebrewing Facebook Group

Is it too late to find FG?

Homebrew Talk

Help Support Homebrew Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

DoubleO

Member
Joined
Feb 10, 2011
Messages
7
Reaction score
0
Location
Stone Mountain
I brewed my first batch last week and took an OG reading. Last night I bottled and forgot to get a FG reading. Can I get an accurate FG after carbonation? I really don't want to open one of the bottles. Also, is there a way to find ABV without the FG?
 
No you cannot take a reading now and get the same reading as you would before priming and bottling. You added more sugar to the beer which will make your reading higher.

ABV is calculated using OG and FG. If you used an all extract brew, your instructions should tell you what the ABV is.

How long did you keep it in primary?
 
I let it sit in the primary for 7 days and it is an all extract brew. My OG was exactly what my instructions said it would be, so I guess my ABV can't be off too much, if any.

Thanks!
 
I let it sit in the primary for 7 days and it is an all extract brew. My OG was exactly what my instructions said it would be, so I guess my ABV can't be off too much, if any.

Thanks!

How did you judge that your brew was ready to be bottled w/o a FG reading on multiple days? I too am new to brewing, but you might have bottled too soon. If you did there is a chance that you might have bottle bombs. I could be very wrong, but it might be a good idea to place the bottles in a spot that if they do go, they wont hurt anyone or anything. Please don;t take this as a guarantee, just a safety tip if it does happen.
 
I let it sit in the primary for 7 days and it is an all extract brew. My OG was exactly what my instructions said it would be, so I guess my ABV can't be off too much, if any.

Thanks!

Throw away the instructions after you use them for brewing. The only way you know your beer is done is if you take a steady reading a few days in a row...even then, leave the beer where it is. 3 weeks is a good starting point. Sometimes I don't even take readings until I reach 3 weeks in the primary.

You definitely could have bottle bombs if the yeast wasn't done doing its thing.
 
Can I get an accurate FG after carbonation?

yes, but you need to degas the beer first. once the beer is completely degassed (may take overnight), take your hydrometer reading then subtract about 0.5 point per oz of priming sugar used, i.e. if you read an FG of 1.014 and used 4 oz of priming sugar, then your true FG is 1.012

also, in the future do not go by kit instructions or bubbling as a measure of doneness
 
yes, but you need to degas the beer first. once the beer is completely degassed (may take overnight), take your hydrometer reading then subtract about 0.5 point per oz of priming sugar used, i.e. if you read an FG of 1.014 and used 4 oz of priming sugar, then your true FG is 1.012

also, in the future do not go by kit instructions or bubbling as a measure of doneness

This can be done but still not very accurate. And even if it was accurate, what's done is done. If the fermenting hasn't completely finished, it isn't like you can pour all those bottles in the fermenter again. Taking the FG now is kind of pointless.
 
This can be done but still not very accurate. And even if it was accurate, what's done is done. If the fermenting hasn't completely finished, it isn't like you can pour all those bottles in the fermenter again. Taking the FG now is kind of pointless.

its not pointless if he wants a clue what his abv is. and why couldnt you pour all the bottles back in the fermenter if it wasnt done? its not like the yeast disappear or more cant be added to it
 
dcp27 said:
its not pointless if he wants a clue what his abv is. and why couldnt you pour all the bottles back in the fermenter if it wasnt done? its not like the yeast disappear or more cant be added to it

If he wants to open all those bottles and pour them in just for abv, he can but I don't find that to be the best thing to do. Pouring 48 bottles in a bucket will diffently put a lot of o2 into the beer. If he wants to know abv, just look on the instructions. Extract brewing is usually right on to the estimates.
 
If he wants to open all those bottles and pour them in just for abv, he can but I don't find that to be the best thing to do. Pouring 48 bottles in a bucket will diffently put a lot of o2 into the beer. If he wants to know abv, just look on the instructions. Extract brewing is usually right on to the estimates.

Actually, only OG is right on for extract brewing. Many people suffer the "curse of 1.02" with extract kits and like with every brew, FG is just an estimate since theres many factors that contribute to it. The only way to know your FG is to actually take a reading for it, which can easily be done at this point with a fair amount of accuracy.

Also, I didn't say to dump it all to get an FG, you need less than a bottle for that. I said theres no reason you couldn't pour it all back in the fermenter if it wasn't finished fermenting, which if done carefully would add no O2 into it. It'd be annoying, but I'd risk slight oxidation over 50 exploding bottles personally.
 
dcp27 said:
Actually, only OG is right on for extract brewing. Many people suffer the "curse of 1.02" with extract kits and like with every brew, FG is just an estimate since theres many factors that contribute to it. The only way to know your FG is to actually take a reading for it, which can easily be done at this point with a fair amount of accuracy.

Also, I didn't say to dump it all to get an FG, you need less than a bottle for that. I said theres no reason you couldn't pour it all back in the fermenter if it wasn't finished fermenting, which if done carefully would add no O2 into it. It'd be annoying, but I'd risk slight oxidation over 50 exploding bottles personally.

I find my og, fg, and abv to be really close to the estimate each time. Yes, to actually know your beer is done fermenting you need to take a gravity reading. If done now, wouldn't his gravity be higher because the priming sugar was added? So if he took it from a bottle, he really wouldn't know if it was done or not.
 
OK lesson learned. Next batch I'll slow down and cover all the bases.

They have been bottled for a day and a half with no problem. If the bottles were going to pop, about how long would it take for them to get to that point?
 
I let it sit in the primary for 7 days and it is an all extract brew. My OG was exactly what my instructions said it would be, so I guess my ABV can't be off too much, if any.

Thanks!

What I want to know is where did you get the idea to bottle after 7 days? You certainly have not been paying attention here.
 
Since OP just bottled it, yes it would be higher, but like I said several posts ago, that amount higher is easily calculated (~0.5 point per oz of priming sugar). If OP waits til its carbed, then no it won't be higher since sugar is 100% fermentable. Really, whats the harm in losing 1/2 bottle (unless you want to drink it flat) to find out something you want to know?
 
wolverinebrewer said:
What I want to know is where did you get the idea to bottle after 7 days? You certainly have not been paying attention here.

Well he has only posted 5 times so maybe he just found HBT. A lot of the extract instructions say bottle no later than 7 to 10 days. If you don't research on here It buy a book, you would never know 3 weeks was the minimum time.
 
dcp27 said:
Since OP just bottled it, yes it would be higher, but like I said several posts ago, that amount higher is easily calculated (~0.5 point per oz of priming sugar). If OP waits til its carbed, then no it won't be higher since sugar is 100% fermentable. Really, whats the harm in losing 1/2 bottle (unless you want to drink it flat) to find out something you want to know?

Oh there is no harm in wasting a bottle to find out the abv. I personally don't know if I would pour them back into primary. I might just go with it lol

So if you use 3.5 ounces of sugar and your reading is 1.014, your real fg would be 1.01225?
 
What I want to know is where did you get the idea to bottle after 7 days? You certainly have not been paying attention here.

The first things I noticed when I started "paying attention" was that if I talk to 10 people I would get 10 different answers. The second thing I noticed was that everyone’s opinion was based on their own brewing experiences. I chose to follow the instructions in my kit, even though some people say ignore them. It called for 5 to 7 days, I went with 7. I've seen people say 10 days, 3 weeks, 1 month, and some are going longer. When all is said and done, I'll have my own experience to improve on. If it turns out bad, guess what, next time it will be better. This process would not be fun to me if I didn't learn as I go.
 
DoubleO said:
The first things I noticed when I started "paying attention" was that if I talk to 10 people I would get 10 different answers. The second thing I noticed was that everyone’s opinion was based on their own brewing experiences. I chose to follow the instructions in my kit, even though some people say ignore them. It called for 5 to 7 days, I went with 7. I've seen people say 10 days, 3 weeks, 1 month, and some are going longer. When all is said and done, I'll have my own experience to improve on. If it turns out bad, guess what, next time it will be better. This process would not be fun to me if I didn't learn as I go.

This is true to a certain point. You will read 9 times out of 10 that keeping your beer in primary at least 3 weeks is the best way to go. And there are a ton of reasons why.

Learning by making mistakes is a good way to get better at brewing. I personally like to read a bunch before I try something.
 
So if you use 3.5 ounces of sugar and your reading is 1.014, your real fg would be 1.01225?

yup, given it hasn't fermented yet and its a 5gal batch. If it has carbed, then 1.014 is your real FG

The first things I noticed when I started "paying attention" was that if I talk to 10 people I would get 10 different answers. The second thing I noticed was that everyone’s opinion was based on their own brewing experiences. I chose to follow the instructions in my kit, even though some people say ignore them. It called for 5 to 7 days, I went with 7. I've seen people say 10 days, 3 weeks, 1 month, and some are going longer. When all is said and done, I'll have my own experience to improve on. If it turns out bad, guess what, next time it will be better. This process would not be fun to me if I didn't learn as I go.

One of the main reasons we say not to follow the instructions with the kit is because while 5-7 days is usually long enough to complete fermentation, if you have lower temps, longer lag, old yeast, etc etc, then it may not be enough time. The only true way to know fermentation is complete is by taking an FG reading. How long you wait after fermentation is complete is up to you, but the general consensus is that longer time improves the beer as it gives the yeast more time to clean up their byproducts and lets it clarify. unfortunately, patience is very tough in the beginning.
 
While read the responses, some more questions have come to mind. I thought exposing the beer to light and oxygen was supposed to be avoided. How do you take FG readings multiple times over a few days? Or is it ok to open and close the primary briefly? What happens if it is exposed to too much of either? Also, what do you do with the sample used to get the reading, dump it or put it back in?
 
DoubleO said:
While read the responses, some more questions have come to mind. I thought exposing the beer to light and oxygen was supposed to be avoided. How do you take FG readings multiple times over a few days? Or is it ok to open and close the primary briefly? What happens if it is exposed to too much of either? Also, what do you do with the sample used to get the reading, dump it or put it back in?

The amount of time it takes to open the bucket and take the reading is not enough o2 to do anything.

You can put it back in if you sanitize everything first but I usually just put it in a cup and try it.
 
CO2 is heavier than air, so as long as you dont disturb it too much, it should still leave a nice blanket of CO2 over the wort.
the only light that is an issue is flourescent or UV, but the briefness of that exposure isn't enough to skunk it anyway.
 
Back
Top