I am consistently coming up 2 to 3 points lower then BeerSmith's calculated OG. I'm using the formula:
(pre-boil vol)(pre-boil GU) = (post boil vol)(post boil GU)
My last recipe showed an estimated pre-boil gravity of 9.29 gal and an estimated pre-boil gravity of 1.042. Under the vols tab it shows 7.49 gal for post boil vol and under the fermentation tab it shows estimated original gravity as 1.054. Now if I plug those numbers into the equation to find estimated post boil OG I get:
(9.29 gal)(42) = (7.49 gal)(post boil GU) = 390.18/7.49 = 52 which is what I actually ended up getting.
If I consider the 4% cooling shrinkage then I can get the same number as BeerSmith
(9.29 gal)(42) = (7.49 gal)(.96 cooling shrinkage)(post boil GU) = 390.18/7.1904 = 54
If this is how estimated OG is being calculated then I'm not sure I understand why. It seems like the estimated pre-boil volume includes the 4% cooling shrinkage so if we take it out on the right side of the equation we would need to take it out on the left side as well correct?
I'm trying to figure out why my actual OG numbers are usually 2 points lower the BeerSmith's calculated OG and after spending a few hours thinking about this and looking at past recipes this is what I came up with. What am I doing wrong?
My equipment profile is setup for 1.8 gal / hr boil off, 4% cooling shrinkage, 1.2 gal loss to trub and chiller, and lauter tun deadspace is set to 1.04 gal.
My procedure is I collect my mash run-offs into my boil kettle and collect the pre-boil volume that BeerSmith says to collect. I check my gravity and if I'm off from BeerSmith's number I adjust my tot efficiency number under the design tab until BeerSmith's estimated pre-boil gravity matches my actual pre-boil gravity. I then boil for the set time and then run through a counter flow wort chiller into the fermenter. I then take my OG reading, then aerate, and then add yeast.
Any help would be greatly appreciated.
Thanks,
Scott
(pre-boil vol)(pre-boil GU) = (post boil vol)(post boil GU)
My last recipe showed an estimated pre-boil gravity of 9.29 gal and an estimated pre-boil gravity of 1.042. Under the vols tab it shows 7.49 gal for post boil vol and under the fermentation tab it shows estimated original gravity as 1.054. Now if I plug those numbers into the equation to find estimated post boil OG I get:
(9.29 gal)(42) = (7.49 gal)(post boil GU) = 390.18/7.49 = 52 which is what I actually ended up getting.
If I consider the 4% cooling shrinkage then I can get the same number as BeerSmith
(9.29 gal)(42) = (7.49 gal)(.96 cooling shrinkage)(post boil GU) = 390.18/7.1904 = 54
If this is how estimated OG is being calculated then I'm not sure I understand why. It seems like the estimated pre-boil volume includes the 4% cooling shrinkage so if we take it out on the right side of the equation we would need to take it out on the left side as well correct?
I'm trying to figure out why my actual OG numbers are usually 2 points lower the BeerSmith's calculated OG and after spending a few hours thinking about this and looking at past recipes this is what I came up with. What am I doing wrong?
My equipment profile is setup for 1.8 gal / hr boil off, 4% cooling shrinkage, 1.2 gal loss to trub and chiller, and lauter tun deadspace is set to 1.04 gal.
My procedure is I collect my mash run-offs into my boil kettle and collect the pre-boil volume that BeerSmith says to collect. I check my gravity and if I'm off from BeerSmith's number I adjust my tot efficiency number under the design tab until BeerSmith's estimated pre-boil gravity matches my actual pre-boil gravity. I then boil for the set time and then run through a counter flow wort chiller into the fermenter. I then take my OG reading, then aerate, and then add yeast.
Any help would be greatly appreciated.
Thanks,
Scott