Low ABV need help! First AG.

[opXus]

OK so I brewed my first AG. The ABV seems to be low by about 1%. Hopefully you can tell me this is just a rookie mistake and can tell me where i went wrong.

Brewed the Caribou Slobber (AG) kit from northern brewer.

Roughly 10lbs of grain.

Forget the quantities (forgot to write down) of mash vs sparge water used, but for mash poured in water at 166 degrees for a one hour mash hoping to be around 153 degrees. I averaged 151 degrees during mash.

Then batch sparged the with remaining water.(forget the amount of water again) Mash and sparge water totaled about 8.5 gallons for a 5 gallon batch. (got 8.5 using an online calculator)

Pre boil gravity 1.038
After boil OG 1.046 (Should have been 1.052 per northern brewer)
Final gravity 1.011

My calculations show ABV 3.7%

Did i calculate wrong? Too low mash temp? Or other?

Any input would be appreciated.

Thanks! LOVE this forum!

opXus

 

[NordeastBrewer77]

i got 4.6%, you musta calculated wrong. abv=OG-FG*131.25

 

[opXus]

OK, thanks the formula i found to calculate was diff than the one you used. So the formula i used must have been posted somewhere by some shemp!

Cheers to you!

:rockin: I'm much happier now!

 

[ThreeWiseMonkeys]

Agreed with Nordeast. There are a ton of good websites with brewing calculators on them. I like brewersfriend.com. Their calculator puts you at 4.6% as well

 

[Golddiggie]

You can also use the Rooftop Brew calculator... The latest update of BeerSmith has become much more accurate for ABV calculations too (matches Rooftop now). Rooftop puts you at 4.7% ABV.

 

[NordeastBrewer77]

OK, thanks the formula i found to calculate was diff than the one you used. So the formula i used must have been posted somewhere by some shemp!

Cheers to you!

:rockin: I'm much happier now!

i remember seeing a few different formulas when i started out. the complete joy says OG-FG*131 is right, but i think 131.25 is right, it jives with the online and software based calks i've used. just glad it remembered it for you off my head so i didn't have to plug it into my software to get it.

 

[opXus]

Thank you folks! This is why i LOVE this forum!

Quick responses to my newbie questions!

Sad thing is i used brewersfriend.com for some other items. Just didnt use the ABV calc.

Now im much happier and ill be enjoying my beer in about a weeks time after bottle conditioning! Since my very first beer (extract kit) is almost gone!

BTW this was my first AG and only my 2nd batch ever!

 

[JoyousRuction]

My 3rd batch was all grain, and I have not been back to extract brewing since then.

It seems like your first post mentioned that you missed your target OG by a few points (1.046 instead of 1.052). You should use this information to calculate your efficiency (probably something like 65%) and use that to adjust recipes in the future (it looks like northern brewer assumed 75%).

 

[diablodawg]

I had the same problem starting out (like last month ) now I just keep some DME ready to boil up and add to the kettle whilst it is cooling to meet the correct OG.

 

[Joppo]

I think you calculated the ABW not ABV.