Malto-Dextrine.

Does anyone have reference to specifics on how much MD increases your gravity readings?

I played with my last porter batch and added 8 oz. to the boil at 15min.
I knew my OG/FG readings would probably be higher based on the addition, but for future reference are there any specifics to how many points specific quantities would raise it?

The beer is really great so far, but the FG was a good 8-10 points higher than I expected based on the parameters of previous batches. (OG 1.068 / FG 1.024)

I would guess 42 points per pound per gallon. So, 42 divded by 2 (for 8oz) is 21 divided by 5 gallons = 4.2 points OG. It is about 12% fermentable so 4.2 points times .88 =3.696 FG addition. You probably had some stuck fermentation to go along with it.

Forrest

Math!

Thanks. I wondered about my attenuation, but I'd never tossed the MD in there before so I wasn't sure how much of an effect it had.

Thanks for the calculation, I just need to find my abacus...

I don't remember where and I'm too lazy to look it up, but I know John Palmer's how to brew has the figure for it somewhere. From memory, it's pretty similar to what Forrest said.