Final A.B.V

Even the simplest formulae (with a single factor of 131 or some other number close to that) don't ignore it. It's just that the corrections embedded in those simplest versions aren't very good as the beer gets bigger. I would be surprised if most people are using pencil and paper to calculate their ABV. There are scads of calculators on line, at least one of which (Brewer's Friend IIRC) gives you the option of the improved formula. BrewCipher does also.

 

For people using online calculators, the hydrometer versus refractometer debate is meaningless in the context of accuracy. The 'refractometer doesn't work post-fermentation' comment only has meaning in a pencil and paper world (the refractometer reading needs to be adjusted, the hydrometer, arguably, does not).

FWIW, there is no 'correction' for OG built into the 131-ish calculations. It's only accurate at a some reference OG (I don't know what that value is). It simply uses the difference between OG and FG to calculate ABV. The problem is that FG becomes a less accurate estimate of residual sugar as the OG changes from that reference value. (A beer with an OG/FG of 1.050/1.010, for example, has less residual sugar than a 1.100/1.010 beer. The '131' formula doesn't care.)

 

One beer I was involved with calculated to have a higher ABV using the formula we all know than the Alton Paar Beer Analyzer measured. The pros said to use the number from the device.

 

True. That's beyond my pay grade, though. I've never heard of a homebrewer doing this. Interesting.

 

My point is that a refractometer is great for checking the SG on the fly, i.e. after mash, collecting wort. Using a test tube and hydrometer in this setting would be cumbersome. On the other hand, because you don't have to check the SG in these scenarios just doing extract, you can simply use a hydrometer.

Yes, you are correct. I meant "refractometer", not "hydrometer". My morning coffee hadn't kicked in yet. And since I'm learning that at least some of you use refractometers post-fermentation, I'll have to try an experiment and see what my next batch looks like in terms of FG between hydrometer and refractrometer (w/ calculation). I do agree that the act of using a refractometer is much easier than that of the hydrometer.

 

Carboy caps and CO2 bottle and regulator, flush the receiving carboy and push genly with 2 PSI or less out of the fermenter carboy. Vent the receiving carboy with a hose in a jar of sanitizer to make an airlock.

Conical and corney kegs, have a purged keg, hook up to conical, push gently out of the conical into the corny. Put hose on a gas out disconnect into a jar of sanitizer to make an air lock.

Edit - do not use over 2 PSI on a carboy. Do not clamp on the cap, it is the blow off valve if the pressure gets too high.

 

I call it a correction because it does account for the density of alcohol in a way that makes it accurate for a specific case. IOW, it's not simply the answer you would get by assuming that apparent attenuation was real attenuation. For all other cases, it becomes a less accurate approximation. Also, the case that it's accurate for isn't even really even one OG. In a sense it's worse than that... It's actually a specific OG/FG pair that it's accurate for.

 

Most hydrometers are calibarated at 60°F; therefore...a 1.012 specific gravity measured at 75°F is actually 1.014.

 

Fascinating discussion of the non-linearity of the change in gravity and its relationship to ABV as adjusted for temperature. But am I the only one here to pick up on the fact this is the OP's first brew and he's contemplating bottling seven days into fermentation?

For the OP: no darts here, but pretty sure this would give poor results. I hope you read the link I posted above which explains the science behind why you want to defer bottling (and racking) so early. Every brewer wants to start drinking their first brew immediately and this is simply the wrong approach. Your average beer needs closer to 6 weeks before it will ready to drink. Putting it in the bottle earlier just lets you look at it earlier. If you leave it in the fermentor there is a good chance it will improve. Impatient brewers are often drinking the last bottle of a batch about the time they should be drinking the first.

Sorry for the interrupt . . . now back to the debate on the physics of water and ethanol.

 

True, but this is far from a pro. Most homebrewers don't do this, and this guy is just working on his first beer.
Why complicate things needlessly.

 

I don't think hopfenumaltz was really talking to the OP at the time of that post. He was just challenging a statement that said transferring to secondary introduces oxygen. Even though it's unlikely to apply to the OP right now, it's educational for him and others. People google up advice all the time, so I can see why someone would want to tell the rest of the story.

 

As Vikeman says, my reply was for the other guy, not the OP.

There are many ways to brew, one can always improve the process as their knowledge increases.

 

Sadly...no.

Loc. cit.
http://www.beeradvocate.com/community/threads/final-a-b-v.199992/#post-2652855