weird way of adjusting wort gravity? - Home Brew Forums

 Home Brew Forums > weird way of adjusting wort gravity?

07-08-2008, 01:17 AM   #1
beretta

Recipes

Mar 2008
Posts: 111
Liked 4 Times on 4 Posts

Hello fellow brewers. !First Post Alert!

I have been brewing beer for 4-5 years, and last year I switched to all grain brewing. Early on, I used to have trouble controlling my OG. Some beers where too small, and some where too big. I figure this had a lot to do with my then constantly changing mashing methods. I since developed a way to adjust my pre-boil gravity to usually "peg" my target OG.
First I figure out my target OG in terms of total sugars. Say my target OG is 1.050 at a 5 gallon batch. Then my target gravity-points would be 50. (drop the "1.0") Then multiply by my length - 5 gallons. Giving me result of 250 pts*gals.
I know from dozens of mashes that I acheive about 30 pts*gals per lb of grain. So I divide the taget 250 pts*gals by 30 and I get 8.33 lbs of grain. I usually throw in about 1 extra lb of grain because I'll adjust my preboil volume DOWN to my target - and I get a healthy amount of extra wort to krausen/carbonate/starter with.
After the sparge/lauter, I mix my wort up in the kettle because I found that the first runnings (heavy SG) from the lauter sticks to the bottom of the brew kettle, and the low density late runnings stick towards the top, or simply put the wort is stratified. After mixing I take a temperature adjusted SG and volume reading. Lets say I end up with SG=1.040 and 7 gallons.
I then calculate the pts*gals of the pre-boil wort: 40 x 7= 280 pts*gals. My target is 250. so I adjust remove wort to compensate:
280 - 250 = 30 pts*gals - This is what I have to "remove" from the boil. Knowing that my wort is 1.040 sg (or 40 sg points) I know that I need to remove 30 pts*gals / 40 pts = .75 gals. I then remove this much wort - .75 gallons.
Now my pre-boil length is now 7 gals - .75 gals = 6.25 gals. I know from records that I'll loose just that much during a 60 minute boil. But if I need more pre-boil volume, I'll add some fresh water, to adjust. (most times I have to add a quart or two of water)
After my boil, I usually end up with a perfect target OG; in this example 1.050 or 50 pts.
I've never read or heard of this technique. It seems to work great. But I'm wondering if I'm strange for over-doing the target OG thing, to the detriment of my brew. I know my yeast bank pretty good, and I usually hit my ABV by .1 - .2 %.

Any questions, comments, concerns, laughter, or flames?

07-08-2008, 01:22 AM   #2
FlyGuy

Recipes

Jan 2007
Calgary, Alberta
Posts: 3,605
Liked 183 Times on 53 Posts

Welcome to HBT! Great first post.

I use a somewhat similar method when batch sparging. I monitor the gravity of my runnings to determine whether I will undershoot or overshoot my target pre-boil gravity. But instead of purposely over-shooting and removing some wort, I adjust the amount of sparge water I use and compensate with a longer boil, if necessary (or top-up with water if I over-shoot). I also use brewing software to do the calcs (I am just lazy).

07-08-2008, 01:31 AM   #3
Special Hops
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Jun 2008
Kanatenah
Posts: 1,443
Liked 28 Times on 25 Posts

I'm gonna have to read that one more time.

07-08-2008, 03:11 AM   #4
jagg
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Nov 2006
North Central NC
Posts: 521
Liked 2 Times on 2 Posts

Quote:
 Originally Posted by Special Hops I'm gonna have to read that one more time.
I did reread it Welcome to HBT Beretta, I have never heard it explained like that before, but I just might try it sometime, thats what I like about this forum, you learn something everyday, keep on brewing

07-08-2008, 07:15 AM   #5
Kauai_Kahuna
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May 2008
Hawaii
Posts: 2,274
Liked 11 Times on 11 Posts

Very nice posting and I'm taking notes. Thank you.