OG Gravity is Higher the Day After Boil?

[maltoftheearth]

Saturday I made a wort with 7lbs pilsner, 2 lbs munich and 1 lb carapils. After cooling I took a reading of an adjusted 1.042 at 75F. Others present confirmed this reading. This was very frustrating b/c my estimated OG was more like 1.050.

I was brewing away from my house. Got the wort home and tossed it in a freezer chest with some lagers at 40F. 24 hours later I boil up and then cool down some DME to increase the gravity in my wort. Before adding the DME I take a gravity reading and guess what? It reads 1.050.

Can anyone explain what is happening here? The hydrometer correction for wort at 40F is +.001 or, at most, +.002.

I have been having issues with gravity lately (consistently low) but maybe it is possible that those "issues" really were low readings following the boil? I was gifted two new hydrometers over the holidays and my low readings have come from one of the hydrometers (but I have tested and they both give the same readings in the same wort.)

 

[william_shakes_beer]

Its hard to fully integtrate the wort and the topoff water just by stirring. Most likely the yeasties have begun doing their thing and mixed the water in completely for you, making your later reading more accurate.

 

[maltoftheearth]

Its hard to fully integtrate the wort and the topoff water just by stirring. Most likely the yeasties have begun doing their thing and mixed the water in completely for you, making your later reading more accurate.

Unfortunately there was no topoff water AND I have yet to pitch the yeast. Good suggestions, though.

Typically I cool my wort overnight to the temperature at which I want to pitch my yeast. So, the measurement I took was only wort that had been boiled -- no DME addition and no yeast.

 

[homebrewdad]

If no topoff and no yeast, then it has to be either a bad hydrometer or operator error.

I recently pulled a gravity reading where the gravity had gone up, and I was perplexed. I spun the thief, tapped it to release bubbles, etc.

My issue? Dummy hadn't pulled quite enough wort into the thief, so the hydrometer physically could not settle any further. D'oh.

 

[maltoftheearth]

Well it's not operator error, at least in the way you described. I had four people check it on Saturday and a second knowledgeable observer check it on Sunday.

I have two of the same hydrometer and both have been tested to give the same readings. OR, I should say, I HAD two ... I broke the offending hydrometer by mistake late on Sunday night.

I think maybe the only solution is a new hydrometer from a different manufacturer. Never had these issues before these new hydrometers.

 

[TopherM]

1.042 at 75F is an actual OG reading of 1.0437.
1.050 at 40F is an actual OG reading of 1.0491.

That's 0.0054 difference. I know that I find it personally VERY difficult to accurately read the HUNDRETHS marking on my hydrometer accurately, especially when there is a little froth on the surface of the wort. I think +/- 0.0054 is an acceptable margin of error for a hydrometer reading, myself. You certainly are not going to detect any significant changes in the final characteristics of the beer with that margin of error in the OG.

If you are concerned, maybe invest $30-40 in a decent refractometer? Much easier to read, and automatically adjusts for temp. The only drawback is it can only read OG, not FG (it can't account/read for alcohol density).

 

[JeepDiver]

If you are concerned, maybe invest $30-40 in a decent refractometer? Much easier to read, and automatically adjusts for temp. The only drawback is it can only read OG, not FG (it can't account/read for alcohol density).

They adjust for room tempature temps, not wort temp which will still make a difference.

 

[helibrewer]

Refractometer readings are easily adjusted for alcohol using one of the many conversion programs available. I use nothing but a refractometer for all of my readings.

The few drops used in a boiling wort rapidly cool to within the refractometers ATC range...place the drops on the refractometer, wait approx 30sec to a minute and the reading is adjusted...I boil until I reach my post-boil OG, not by what the clock says.

 

[maltoftheearth]

1.042 at 75F is an actual OG reading of 1.0437.
1.050 at 40F is an actual OG reading of 1.0491.

That's 0.0054 difference. I know that I find it personally VERY difficult to accurately read the HUNDRETHS marking on my hydrometer accurately, especially when there is a little froth on the surface of the wort. I think +/- 0.0054 is an acceptable margin of error for a hydrometer reading, myself. You certainly are not going to detect any significant changes in the final characteristics of the beer with that margin of error in the OG.

If you are concerned, maybe invest $30-40 in a decent refractometer? Much easier to read, and automatically adjusts for temp. The only drawback is it can only read OG, not FG (it can't account/read for alcohol density).

I should have indicated next to ALL gravity readings that these were adjusted for the temperature difference from 60F.

Still looking for help!

 

[scottedk]

Good thread about off gravity readings: https://www.homebrewtalk.com/f39/at...inal-gravity-reading-wrong-dont-panic-289735/

 

[maltoftheearth]

Good thread about off gravity readings: https://www.homebrewtalk.com/f39/at...inal-gravity-reading-wrong-dont-panic-289735/

That is a good thread and gives me some good ideas about what's at work. Thanks, wish I had seen it before posting.