Fancy math ?

hoppybrewster · 01-26-2012, 03:03 AM

Some time ago I read on the big Internet "somewhere" to take the last two numbers of your OG and divide by four and that's your FG for that brew. Ex. 1070. 70 by 4 equals 17.5. So your FG would be 1018. My last 7 brews have proved this theory. Can I get a witness?

**MalFet** · 01-26-2012, 03:05 AM

Well, doing that will give you the final gravity you'd have if you got 75% attenuation. That's a pretty middle of the road kind of fermentation, though some recipes and some yeasts will certainly fall outside that.

hoppybrewster · 01-26-2012, 03:08 AM

Quote:

Originally Posted by MalFet

Well, doing that will give you the final gravity you'd have if you got 75% attenuation. That's a pretty middle of the road kind of fermentation, though some recipes and some yeasts will certainly fall outside that.

I'm not all grain, does that make a difference?

**MalFet** · 01-26-2012, 03:10 AM

Quote:

Originally Posted by hoppybrewster

I'm not all grain, does that make a difference?

Not really. Certainly all grain brewers have some more control over their fermentability, but there are many factors that determine attenuation. 75% is a reasonable rule of thumb, though.

hoppybrewster · 01-26-2012, 03:13 AM

Quote:

Originally Posted by MalFet

Not really. Certainly all grain brewers have some more control over their fermentability, but there are many factors that determine attenuation. 75% is a reasonable rule of thumb, though.

So you don't think I'm doing something wrong then, my beers are good. What could I do to improve those numbers?

**MalFet** · 01-26-2012, 03:17 AM

Quote:

Originally Posted by hoppybrewster

So you don't think I'm doing something wrong then, my beers are good. What could I do to improve those numbers?

Huh? What do you mean by improve? For most beers, you wouldn't want more than 75% attenuation, lest you dry the beer out too much. Higher isn't better; it's just another factor to control.

hoppybrewster · 01-26-2012, 03:22 AM

Quote:

Originally Posted by MalFet

Huh? What do you mean by improve? For most beers, you wouldn't want more than 75% attenuation, lest you dry the beer out too much. Higher isn't better; it's just another factor to control.

I've heard of people adding priming sugar to the primary to boost alcohol, have you done that?

**iaefebs** · 01-26-2012, 03:26 AM

As Malfet said, your rule applies to a beer that attenuates at 75%. It is math.. no more no less. Divide something by 4 and if you have 1/4 left then 3/4 was removed. Not fancy.

**MalFet** · 01-26-2012, 03:35 AM

Quote:

Originally Posted by hoppybrewster

I've heard of people adding priming sugar to the primary to boost alcohol, have you done that?

You can make very strong prison hootch straight out of table sugar, if you want. Some styles benefit from simple sugars, most don't. It'll raise the OG (and thus the alcohol), but you could accomplish that in other, better ways too.

hoppybrewster · 01-26-2012, 03:38 AM

Quote:

Originally Posted by MalFet

You can make very strong prison hootch straight out of table sugar, if you want. Some styles benefit from simple sugars, most don't. It'll raise the OG (and thus the alcohol), but you could accomplish that in other, better ways too.

I'm listening......