Gravity reading

Hello...

got a weird question and i am hoping it is user error. other wise i am confused (not unusual)

i have done two all-grains. both times this has happend.

after i drain my Tun into the boil kettle i take my gravity reading (pre boil?)
before i pitch yeast (and the wort is cooled) i take my gravity reading (Post boil?)

both batches; my pre boil gravity reading was lower than my post boil. is that the way it is suspose to be?

the portor i just did, i took the pre boil reading and it was .022, post boil it was .048

i was just under the impression that the pre should be higher than the post?????

at this point the "target" is completly not the point.

thanks

Pro boil will be lower than post boil. When you boil off water your wort becomes more dense. OG, original gravity, which is the "target" is taken post boil. Pre boil gravity is mainly used to determine system efficiency. Also make sure you correct for temperature. Brew on!

Gravity is a measure of sugars in solution. If you have X "pounds" of sugar in say, 7.5 gallons, and you boil down to 5 gallon of wort, you still have the same X amount of sugar, but in 7.5/5th as much water, so it will be 7.5/5 = 1.5× as concentrated: eg. 1.040 pre-boil to 1.060 post-boil. What pre- and boil- boil volumes did you have? Also, as mentioned: make sure to correct for temperature, and note that temperature adjustment is more incorrect the further you are from the calibration temperature. I would take my mash runnings gravity and pre-boil samples and let them sit out in coffee mugs until the end of the brew day to let them cool off a good bit first.

OK.. thanks folks. guess what i was seeing is what it should be. jsled... one step at a time... hahaha i just started this all that math hurt my dome there for a little bit. haha
but i see what your saying. my pre- was .022 and my post was .048.

when i was looking at the beersmith sheet i "thought" i saw where the pre was larger than the post and that is where all my confusion began.

i'll have to relook at my brewsheet when i get home.

thanks for the help
jake

You may have seen pre-fermentation gravity (original gravity) and post-fermentation gravity (final gravity)?