Lower post boil og than preboil reading

[Staticsouls]

Hey there super newb on deck, and i just brewed 15lbs of 2 row for a smash brew. Preboil reading came in at 1.070 and post boil at 1.060. I was under the impression that gravity would rise with boil off. Is this false info?

 

[Stillraining]

Yes that's impossible..did you correct for temperature?

 

[aeviaanah]

Did you add sugar during boil?

 

[doug293cz]

Yes that's impossible..did you correct for temperature?

Yes, lower post-boil SG (ie OG) than pre-boil SG is impossible, unless you added water to your BK. No sugar is lost during boiling (other than what little might be lost to a boil over, but that also affect volume, so won't give you the results you think you are seeing.)

(Pre-Boil SG - 1) * Pre-Boil Vol has to equal (Post-Boil SG -1) * Post-Boil Vol

If the two numbers are not equal then one of more of the measurements involved is in error. Note that the equality does not hold if water or sugar are added after the pre-boil measurements, and before the post-boil measurements.

In the OP's case lack of temperature corrections is unlikely to be enough of a factor to explain the improper results.

Brew on

 

[Staticsouls]

No sugar or water were added, and the pre boil read was taken from the kettle spout before fire up. Maybe i read the hydrometer wrong the first time. I gather that i am stuck with it as is its now in fermentation and bubbling so oh well.

 

[Pkrd]

This can definitely happen if you're drinking on brew day.

 

[ChuckO]

Quite often the pre-boil wort is not thoroughly mixed, some areas have higher concentration of sugars than other areas. You can take multiple readings from different sections of the wort to get a better idea of the actual concentration.

 

[Staticsouls]

After days of consideration it came to me that i did use a paint mixer to dough in, but usually i just spin it enough to mix the grist, but his time is went full bore for way too long and and got a milky tecture during the mash. Learning curves lol.