How to check gravity post mash

[azazel1024]

So, how the heck do I check it???

I tried checking it post mash by laddling some in to a 1L container I have (smallest that'll take my hydrometer). When the Wort was already up around 190F or so (I thought to check it after mashing and starting to take it up to a boil for hopping).

I came up with a 1.04 gravity measurement. The actual FG was 1.08!

I'll grant I added half a pound of sugar to raise my gravity a little (Belgian Dupple, so I figured somewhat appropriate), however I had already mashed and already dissolved my pound of dark candi sugar in it when I took the 1.04 reading.

Final boil was about 3.3G (shooting for 3.75G, but I lost a little more in the grains than I thought I would, plus a little extra boil down).

Even trying to account for how much water I lost in boiling off and the sugar I added, it seems like the reading was way off. The only resource I found that had gravity corrected readings only goes to 159F for the correction factor.

Also since my hydrometer has (I assume) lead grains in wax as the weight at the bottom and it melted pretty throughly (though it did cool back, mostly in place), heat seems to be an issue.

Should I mash, sparge and then let it cool down slightly (since I am generally mashing out at around 170F with BiaB batch sparging) before taking the gravity reading, and then cool the hydrometer quickly before taking the wort up to a boil? Get a refractometer? Something else?

Thanks.

 

[BlackGoat]

you really should chill down the wort at least to a reasonable temperature before taking measurements, 190 is way too hot to be taking readings with a hydrometer. did your hydrometer come with a plastic tube to store it in? That makes a perfect container to use for taking measurements. In any case, the concentration of the wort during the boil will greatly increase the gravity of the wort, depending on how long you boil for and how much boil off you had.

 

[Guidry]

I usually fill my hydrometer with wort and then stand it up in a pitcher of tap water, maybe throw a couple of ice cubes in the water after about 5 minutes. The wort will cool down pretty quickly with that little volume, then take your reading. No way I would rely on temp correction at that kind of temp.

Or, you could get yourself a refractometer.

 

[NivekD]

Or, you could get yourself a refractometer.

BINGO! I love my refractometer.

 

[rklinck]

BINGO! I love my refractometer.

A refractometer is the only way to go. You only have to use a drop of liquid and don't have to let it cool. You cannot get an accurate read from a hydrometer (even corrected for temp) when it is at those temperatures. So, your only option with a hydrometer is to let the liquid cool to within normal temps.

 

[Begin2Brew]

Hydrometers are calibrated at 60F. 1.040 wort corrected from 190F is 1.073

 

[Travestian]

Hydrometers are calibrated at 60F. 1.040 wort corrected from 190F is 1.073

I do this all the time for my preboil gravities. However I do it at around 140F since that is the average temp for my wort post sparge and all in the kettle. My OG's usually come out fairly accurate compared to preboil gravities when I account for the temperature. The website I use to correct gravities is http://dd26943.com/davesdreaded/tools/convert.htm

 

[hophop]

I use my refractometer too. But I put a wort sample in a small clean jelly jar, then cool that to 60-65 in an ice bath before transferring to the hydrometer cylinder for a back up reading.

 

[BansheeRider]

Refractometers are so worth the $25.

Beer Wort and Wine Refractometer, Dual Scale - Specific Gravity and Brix, replaces homebrew hydrometer
http://amzn.com/B006GG0TDK

 

[Yooper]

Hydrometers are calibrated at 60F. 1.040 wort corrected from 190F is 1.073

'cept it's not.

Oh, I mean, yes it is on the correction table. But take the same sample, cool it to 90 degrees, and THEN look at the correction table, and the first reading is so far off that it's useless.

The sample for a hydrometer really needs to be cooled to under 100 degrees to even come close to being accurate.

 

[azazel1024]

Thanks everyone.