Forgot to Take FG Before Mixing in Priming Sugar

One ounce of corn sugar in a gallon of beer will raise the gravity by 0.002557. Subtract that from your measured gravity.

And yes, if fermentation wasn't finished, it will continue in the bottle. That's why you should take 2 readings, 2-3 days apart, before deciding it's finished.

Edit: make that 0.002750. Worst typo ever.

 

If your target final gravity was 1.011 and you were actually at 1.022 then you may or may not have finished fermenting. Then you added priming sugar and bottled.

Kaboom!

It's possible. It's happened to me. It's happened to lots of us. It will happen to you too...

Put those bottles inside a plastic container with a lid if you want to be safe. If you want to be adventurous, store them right next to your bed without putting them in a plastic container.

 

I used BrewCipher to calculate the sugar's gravity contribution above. Took about 5 seconds. Most standalone priming calculators wouldn't answer the question, because they deal in volumes of CO2 rather than in gravity points.

In this case, a calculator wasn't really needed...
44 points per pound per gallon times 1/16 pounds, divided by 1 gallon

 

If you are 8-9 points from FG, you most assuredly will have bottle bombs.

 

It's more than that. 9 fully fermentable points in one gallon is equivalent to about 3.27 ounces of corn sugar. 3.27 ounces of corn sugar plus the ounce he added (total equiv 4.27 ounces) would produce almost 9 volumes (including residual Co2 from fermentation) in one gallon.

 

Yep. One ounce of corn sugar raises the gravity of one gallon of beer by 2.75 points.
9 points divided by 2.75 points per ounce = residual fermentables equivalent to 3.27 ounces of corn sugar.
So go to any priming calculator and see what 4.27 ounces of corn sugar will do in one gallon.

 

If your gravity is correct, and all the math works..

Your bottles will explode.

You could perhaps give them a couple days, and with some gloves, and glasses, open them, and recap. Should atleast help a bit.

Otherwise, if you have another fridge, I'd give them a week, and allow them to chill, and then try to drink it up. Will probably be too sweet and under attenuated, but it's not a waste and you can refrain from the glass explosions.

 

Since the beer has not been bottled very long yet, wouldn't it be safer to uncap them now, cover each bottle's mouth with aluminum foil for 4-5 days (or maybe longer, that's a tough question), then put new caps on?

 

9 gravity points, i.e. 0.009 of (fermentable) gravity would be an equal problem in any volume of beer. Points (in this context) are unitless. Add to that the extra 2.75 points from the added corn sugar (plus the residual CO2 from fermentation). Kaboom.

 

Possibly. But he'd be guessing really. Not a bad idea. But if he let it go too far there wouldn't be enough to carbonate.

 

Yes, I was. In the context of one gallon at the time. Because I was showing the math for one gallon.

But any beer that will drop 0.009 in SG will make the same volumes of CO2, regardless of the volume of the beer. In a larger batch, that 0.009 of SG will be made up of a larger mass of fermentables, but it will still be 0.009 of SG.

The point (pun intended) is... if you have a beer that would have dropped 0.009 in SG, and you add priming sugar (one ounce to one gallon, 5 ounces to 5 gallons, or 465 ounces to 15 barrels), and then add the residual CO2 volumes from fermentation, you'll get almost 9 Volumes of CO2. Batch size doesn't matter.

 

The difference is that Kai's Remaining Extract formula assumes that if you say there are 'X' points remaining, that there are really less, due to the difference between real and apparent attenuation. (Notice the 0.82 factor in his "delta RE" formula.) My assumption was that there were "really" 'X' points remaining, not "apparently" 'X' points remaining.

In OP's case, it's reasonable to go with Kai's assumption, since we're talking about the difference between his gravity reading and what he was expecting, and those readings/expectations are products of fermentation, including apparent attenuation.

So go with Kai's Remaining Extract formula, plus your 0.9 residual volumes, plus priming sugar...

4.59 volumes from wort yet to be attenuated (Kai's RE formula) +
0.9 residual volumes +
1.87 volumes from one ounce of corn sugar*
-------------
7.36 total volumes

Even with the reasonable assumption that points remaining means apparent points remaining, when you add priming sugar those are "real" points, so you can't apply Kai's RE formula to them.

*The 1.87 comes from most any priming calculator... one gallon, 65F (to get 0.9 residual volumes), one ounce corn sugar, gives 2.77 volumes. Subtract the 0.9 residual, and you get 1.87 volumes. If you use Kai's Corn Sugar formula, you get 1.72 Volumes ("close enough" to 1.87), not the ~1.4 Volumes you'd get by multiplying the points by 0.51. If you use Kai's Corn Sugar formula rather than a calculator, you get 7.21 total volumes vice 7.36. (Also note that an ounce of corn sugar adds about 2.75 points of gravity to a gallon of beer, not 2 points which I believe you are assuming.)

But the takeaway is that Kai's 0.51 volumes per point is valid for Remaining (apparent) Extract, and not for sugar additions. (To be clear, Kai never said it was.)

 

I find it unlikely that after 2 weeks your yeast was going to continue to bring your fg all the way down to 1.011. More likely it stalled for any number of reasons.

 

Yes. I also agree that it's more than 5 volumes. Without a winkie face.

 

Hopefully for OP's sake the gravity was never going to go lower, because stalls can unstall. I think we still haven't seen the recipe though. We could tell from that how realistic the target FG was.

 

No. I just think winkie faces are borderline douchie. Regular smiley faces are cool though.