Missed final gravity on stout??

[houser31]

I missed my final gravity by alot any Ideas how I can change this or help it with my next batch... OG was 1.066 and FG is 1.033... any ideas?

 

[BigFloyd]

What are you using to get your readings?

 

[houser31]

A refractometer

 

[BigFloyd]

A refractometer

Therein lies the problem unless you're running that FG reading through a correction program.

Check with an hydrometer. You may find it close to 1.015-17 which is fine for a stout with all those unfermentables.

 

[houser31]

I'll see what it says using my hydrometer

 

[BigFloyd]

And?

 

[houser31]

It was down to 1.022

 

[AZCoolerBrewer]

Sean Terrill calculator put the SG measurement at 1.014.

 

[houser31]

What's that mean?

 

[TheHopfather]

Refractometers measure the amount of sugar in a liquid (wort in this case), they do not function properly when alcohol is in solution. The refraction is different when alcohol is present, so they do work before any fermentation takes place but afterwards your results will be incorrect. You have to use a correction formula to get an accurate reading after fermentation has taken place.

http://www.brewersfriend.com/refractometer-calculator/ - I like this one.

Every refractometer is different. You actually need to compare the reading on your refractometer and hydrometer over multiple batches to come up with the Wort Correction Factor for your refractometer. I've read that using 1.04 is a good average correction number to use however, but you won't be 100% sure unless you do the leg work yourself.

 

[BigFloyd]

It was down to 1.022

That is probably done for a higher gravity stout (lots of unfermentables there).

Also, if it's a milk stout, one pound of lactose will add .07 to your FG result.