Am I doing this right? I found a formula to convert...but the 2 times I have used it my gravity has been way under what I was shooting for. All grain, batch sparging, etc...Formula was Ingredient item x 3 divided by 5=desired quantity.....sorry if my 30 years out of high school math skills suck...
makes sense to me [though I would go (Item/5) *3)] Are you using the same equipment? Same ratio of waters, planning for similar boil off rate? (that is the one thing that won't go down)
For whatever my input is worth, a 60 min full boil on 1 gal batches (1.54 gal pre-boil) loses half a gallon boil off and roughly a cup to cooling shrinkage on my equipment. I haven't moved up to standard 5 gallon batches so there's only what I've read, which is 1-1.5 gallon average boil off? Numbers like 10-15% total volume boiled off, where I'm in the range of 33% about. I understand these numbers won't scale linearly for you at 3 gallons, but as long as you're hitting your recipes' old 5 gallon batch size pre-boil gravity you should at least make your OG if not overshoot it from a disproportionately higher % of total volume that's boiled off compared to what you're used to. (This makes sense in my head, but anyone feel free to correct me if I'm wrong.) The only real advice I can think to give is maybe your mash tuns' (assuming you're using the same one) dead space is throwing off efficiency? Mine would be even worse than it is if I didn't find a way to keep the half gallon of wort left behind.. I'm only a few years out of high school and I already wish I payed more attention in math, either way good luck with your next brewday!
Here's the thing...with my system I collect 8 gallons of wort. I boil down to 6, which when drained out of my kettle (as the height of the drain leaves a gallon behind) I collect 5 gallons in the fermenter. Beers always seems to come out fine for my liking. Sooooooooo I collect less then 6 and boil down to 4 for 3 in the fermenter....and have been 3 points under gravity each time (twice)....
You can always gather more wort and boil for 10 minutes before you add your first hop addition. This will bring your post boil gravity up. You'll get those 3 points back.
