AG pre boil reading?!

[fretsforlife]

ok so i just mashed over 13 lbs of grain and have collected all the liquor. Ive got just over 6 gallons in my kettle and its reading 1.030! i dont get it.. this is supposed to be a 1.070 beer according to BeerTools.. even if i boil a gallon off, isnt 1.030 still too low? should I add some DME?
thanks,

 

[Suthrncomfrt1884]

Did you adjust the reading for the temperature of the wort? Assuming you didn't, you should have around 1.057 after converting your reading. This is assuming your wort was at 170F.

 

[Reelale]

Yeah, according to beersmith you should be around 1.059 for 6 gallons pre-boil.

 

[fretsforlife]

awesome! you guys just calmed me down some,.. you're right it wasnt a cooled down sample.. thanks a million !!

 

[Yooper]

awesome! you guys just calmed me down some,.. you're right it wasnt a colled down sample.. thanks a million !!

Stick it in the freezer, or cool it in an ice bath. Any reading taken over about 95 degrees is worthless, even with temperature correction. Once it gets under about 90 degrees, those temperature correction charts will be closer. SG readings taken over 100 degrees are notoriously inaccurate.

 

[Reelale]

Stick it in the freezer, or cool it in an ice bath. Any reading taken over about 95 degrees is worthless, even with temperature correction. Once it gets under about 90 degrees, those temperature correction charts will be closer. SG readings taken over 100 degrees are notoriously inaccurate.

Yoop, does that hold true for temperature-correcting refractometers too? I just cool and use the hydrometer, but I need to buy something new!

 

[Yooper]

Yoop, does that hold true for temperature-correcting refractometers too? I just cool and use the hydrometer, but I need to buy something new!

No, the refractometer seems much more accurate. It only takes a few seconds for two drops of wort to cool! The thing is, the ATC refractometers only work for the temperature of the refractometer between 60 and 90 degrees, or something like that. Not a problem usually, but if you're an outdoors brewer, that's something to keep in mind!

 

[Reelale]

Thanks. Off to the refractometer store.....

 

[Suthrncomfrt1884]

Stick it in the freezer, or cool it in an ice bath. Any reading taken over about 95 degrees is worthless, even with temperature correction. Once it gets under about 90 degrees, those temperature correction charts will be closer. SG readings taken over 100 degrees are notoriously inaccurate.

I never realized they were so innaccurate at higher temps. I've always thought my readings were pretty good since I always nail my post-boil OG and it matches up with the pre-boil.

 

[ajf]

The other thing that hasn't been asked yet is did you stir the wort before taking the reading? I forgot to do that once, and got a very low gravity reading. Stirred the wort, and it was right where it ought to have been.

-a.

 

[fretsforlife]

I've taken all of this into consideration, thank you all so much.. I didnt stir and I didnt cool which I know to do now. My cooled O.G. turned out to be 1.060. about 10 points lover than beertools said it'd be, but thats gotta be an efficiency problem. I need to play around with my sparge techniques. So far, im happy with my first AG experience. Its happily fermenting away.

 

[pkeeler]

Any reading taken over about 95 degrees is worthless, even with temperature correction. Once it gets under about 90 degrees, those temperature correction charts will be closer. SG readings taken over 100 degrees are notoriously inaccurate.

I've found the readings to be very accurate using the correction charts. Do you have a source for this info?

 

[Yooper]

I've found the readings to be very accurate using the correction charts. Do you have a source for this info?

Just my own experiences. I can take a reading at 150, let it cool to 90, and then 60, and the readings (using the correction charts) between the 90 degree sample and 60 degree sample are fairly close. The one at 150 is way different, even with the charts.

The delta G value (correction value) has a much bigger differential above 114 degrees or so, and I think that's why it's so much further off.