Lower Gravity After Boil?

[EdmontonBoil]

Today I did my first brew on the Brewzilla and I'm trying to figure out if I had logistical issues or if something weird happened during the boil.

At the end of the mash, when I tested the gravity, it came in at 1.065 @ 80F, after recirculating the wort with the pump for about ten minutes. This was higher than I was expecting, so I double and triple checked the gravity reading. My initial thought was that the wort wasn't mixed thoroughly, but the amount of time I'd had the pump running made me think that it had to be correct.

However, after the boil, the wort measured 1.055 @ 72F (since this was also not what I expected, given the first reading, I double and triple checked it).

Is there any world in which it's possible that this is something other than a measurement error? The only reason why I'd entertain that is that I didn't have time to heat the sparge water (I was trying to get several children ready for dance classes) so I did a cold sparge. I'd normally be inclined to assume that it was a measurement error, but as I noted, I checked a few times and gave the wort a while to circulate with the pump. Any alternate suggestions for the low second reading?

 

[Erik the Anglophile]

At what temps did you check the gravity?
Always get sample down to room temp, there are temperature correction calculators out there for hydrometer readings, but in my experience after double checking they are not very reliable.

 

[Sammy86]

I had this very same phenomenon happen on my 3.11 Brewzilla two brews ago. You gotta make sure the wort is mixed well otherwise you're going to get the initial runnings all from the bottom which are obviously higher in sugar content then the top.

The recirculation alone isn't going to mix the wort well enough to get an accurate reading.

What I do is I pull the grain, vorlauf through the grain bed for 10-15 minutes...sparge, mix the wort with the mash paddle really well and then take a sample and throw it in the freezer/fridge until it gets to temp.

Give it a try and see what happens! For post boil OG i transfer the wort into my FV's through the CFC about halfway before taking a sample and then get my reading...works every time.

 

[EdmontonBoil]

The recirculation alone isn't going to mix the wort well enough to get an accurate reading.

It sounds like this is probably what happened. Good to know that it's happened to someone else as well!