Help understanding FG, ABV and attenuation

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Chrispy92

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Hey everyone I recently brewed a Belgian Quad and am having some trouble figuring out all my numbers.

I bottled it yesterday after this ferm schedule :

28th Nov
18 litres at OG 1.084
Pitched healthy dose of M41

5th Oct
Added liquid sucrose,
estimated OG 1.089

10th Oct
SG at 1.010
Added 245g dried fruit that had soaked on 350ml of dark rum (added rum as well)

28th Oct
FG at 1.000 !?!?! No sign of infection or funk. Bottled

So here's my conundrum, how much do you think the dried fruit added raised my OG. Next, 350ml of rum at 40% ABV is only 2% of my total volume of liquid. How much will this raise the ABV of the total batch?

Finally, the FG .... How much does the alcohol on the sample skew this number?!

I just want to get a close ballpark figure of what my ABV is and better understand this.

Seems like crazy attenuation and I'm slightly worried about how it will turn out.

Thanks in advance
 
The fruit would have added some fermentable sugars. The Rum would raise the ABV. How much I don't know for sure.
How did you measure the FG? If you used a refractometer did you make a correction for the presence of alcohol?

I don't know the calculations that would be needed to figure out how much the rum and fruit would change things, maybe someone else will chime in.
 
No refractomefer, just a good old hydrometer which is adjusted for temperature.

I'm thinking it all may be negligible. As it stands now it's probably around 12.5% ABV. I just hope the M41 will bottle carb! Didn't want it to be this strong fml
 
OK never fear I think I have it figured out!

Used brewers friend to re-enter all my fermentables to replicate the OG I recorded, then added the fruit which takes the OG to 1.093!

If the rum totals 2% of the 17L batch, at 40% abv this will increase the total abv by 0.8% .

Soooo 1.093 --> 1.000 = 12.2% + .08% = 13%abv

FML.... ahhhhh now I fear i will be stuck with forever un-carbonated bottles.

So little info out there about M41's alcohol tolerance, I have seen one reference to 12% so Im feeling a little sad. So much wasted time and effort if it won't carb up in the bottles. :(
 
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