Increase in gravity over a 60 minute boil

ive made a dip stick i can place in the kettle that is calibrated to specific volumes in the kettle. i use it to get my initial pre boil volume and my final volume.

based on these measurements, i know i boil at a rate of just about 1 gal / hr. this is probably a very common boiling rate.

you can use the dilution tool in BS2 to estimate the effect of water on gravity. per instance, if im planning on making a 5 gallon 1.050 beer, at 6 gallons my gravity should be 1.042. dont forget to account for temperature effect on gravity when you take your measurements as well. you can use the hydrometer adjust tool for this!

one final trick. i usually boil for 90 minutes - a little past my final OG - then add back some boiled water to nail my og exact. that little trick helps me account for slight varaitions in batch-to-batch efficiency/boil off rate.

 

Not sure what you mean by 'losing some', but if preboil is 51 GP and volume is 8 gallons, that's 408 total GP. If you boil it down to 5.25 gallons, 408/5.25 = 77.7 GP/gal. That's it, same for every beer no matter what.

 

I believe that the OP's 5.25 gallons is volume delivered to the fermenter, not post-boil volume in kettle (for which your calculation is entirely correct). To the OP: you need to accurately figure your losses (in transferring from kettle to fermenter) in order to be able to answer your question.

 

I try not to over complicate things. Once you get a volume into your kettle you DON'T lose any gravity points. From here on out you lose volume. You may lose a little potential gravity to your wort chiller, but I don't think you'll see that even measure out in brix or gravity on a hydrometer. More likely you'll lose a few drops off your batch volume and it's no sweat.

To answer one of your questions, it's always about potential gravity (or sugar, as we'll call it) divided by volume.

1 gal of 1.025 wort boiled down to 1/2 gal would be 1.050 wort
1 gal of 1.050 wort boiled down to 1/2 gal would be 1.100 wort

(This is @ 60F probably at sea level).

If you halve the volume you will double the gravity.

 

"When am I ever gonna use this stupid Algebra!?!?!?" - unknown

 

Well, to be fair, I've solved for X more since I started homebrewing than I did in the preceding 10 years after high school.

 

You need to shoot for a higher post boil volume. Assuming your new chiller loss is the only issue, you'll need to add the chiller loss volume to your total (old) starting water (either the mash/sparge water if all grain, or the kettle starting water if extract).

If All Grain... the extra water will cause a mash efficiency increase, but not enough to overcome the new (chiller) loss. So you'll need to adjust grain bills upward. Sorry...leaving sugar in the chiller means you need more sugar.

If extract...the extra water will cause a lower OG, so you'll need to adjust your LME/DME amounts upward.