Did not take OG - is FG useless?

[Retiredguns]

I've brewed a dozen or so of the Muntons & Brewferm LME (can) kits and all but a couple turned out rather well. I finally bought a hydrometer, but not until after my current batch has been fermenting for 9 days. The meter reads about 1.018 and Brewferm says the OG is around 1.075-ish. I think it is supposed to finish around 1.013. Just wondering how long to let it sit until I bottle? I haven't a clue about abv either. This is a 2.5gl brew. I probably should have added some malt or sugar to the recipe, but if it comes out a 3.2 beer then I'll just have to drink more! From here on out I'll of course measure correctly.

Thanks
Steve

 

[jtratcliff]

Give it another few days and check FG again... If it's the same, you're probably done.

In general, if you're in the approximate vicinity of your expected FG and your gravity readings taken a few days apart stay stable, you're good to bottle.

I do BIAB but I've heard other extract brewers mention a "1.020 wall" that extract sometimes hits for some reason, so 1.018 may be as low as you get.

 

[Hoppity]

ABV calculators abound on the web, but notwithstanding temp corrections, the standard rule of thumb is 1.31x the difference between OG and FG. Unless you screwed up the kit, I'd assume you hit OG, congratulate yourself and take good tasting notes. Don't bottle until FG is stable for at least 3 days. Follow priming instructions and try to minimize agitation and exposure to O2.

 

[andy6026]

Given that you know what the OG of the kit is supposed to be, and assuming you added the right volumes of water and can/lme, then you can safely guess that you hit within the ballpark of the kits intended OG of 1.075, if you didn't hit it exactly.

You can now use an online calculator such as this one to calculate your final ABV, or do the calculation manually as an above poster showed you):

http://www.brewersfriend.com/abv-calculator/

I plugged in your numbers and it should come out to 8.4% - a fairly big beer - perfect for a IIPA.

FG reading isn't useless if you missed taking an OG- it can at least confirm the FG portion of the above calculation as well as tell you when the beer is done fermenting.

 

[unionrdr]

I've seen some eight different formulas for ABV calculation. Since the Cooper's ABV formula fits BS2's ABV range, I use it; (OG-FG)/7.46 + .5= ABV%. So (1075-1018)= 57/7.46 = 7.64075...rounded to 7.64 + .5 = 8.14% ABV. With a OG of 1.075, I'd say 1.018 is about right.