Post boil gravity = Pre-boil gravity

[Simonpyman]

So I did a Vanilla porter this morning and my pre-boil gravity was 1.050 based on the hydrometer reading at room temp. Once the boil was done i took another reading and it was the same. My tilt is also reading the same as well.
What could have happened? Apart from a lower ABV i think I am ok. I was shooting for an estimated OG of 1.056 so not too far off.

 

[Minbari]

How long did you boil?
Boiled uncovered?

Obviously the sugars that were there before boil are still there, but 1/2-1 gallon of water should be gone, making gravity higher. Unless you topped it up after boil.

 

[Simonpyman]

How long did you boil?
Boiled uncovered?

Obviously the sugars that were there before boil are still there, but 1/2-1 gallon of water should be gone, making gravity higher. Unless you topped it up after boil.

Boiled for 75 minutes uncovered and did not add any water after boil.

 

[Donoroto]

I might guess measurement error, but which kind?

 

[Minbari]

Boiled for 75 minutes uncovered and did not add any water after boil.

Then I would have to say your initial SG reading was wrong.

Maybe you didn't stir it up?

 

[Simonpyman]

Then I would have to say your initial SG reading was wrong.

Maybe you didn't stir it up?

Ha, maybe. That’s a good point haha

 

[Minbari]

Ha, maybe. That’s a good point haha

I have had difference of 40 pts. Unboiled wort seems to settle out pretty fast. I always stir it before taking a reading

 

[Simonpyman]

I have had difference of 40 pts. Unboiled wort seems to settle out pretty fast. I always stir it before taking a reading

Good to know, I will make sure to stir in the future! For some reason i assumed that the wort unboiled or boiled would be uniform/well mixed . I did fill up the graduated cylinder using the pump/recirc arm for each measurement so i would have thought that not an issue

 

[Zambi]

I would also vote for stirring.

There could also be a temperature difference if your unboiled wort was a different temp than your boiled when measuring.
But that wouldn't be such a big difference

 

[BarbarianBrewer]

So I did a Vanilla porter this morning and my pre-boil gravity was 1.050 based on the hydrometer reading at room temp. Once the boil was done i took another reading and it was the same. My tilt is also reading the same as well.
What could have happened? Apart from a lower ABV i think I am ok. I was shooting for an estimated OG of 1.056 so not too far off.

I would assume you only used your tilt for the post-boil/fermenter reading. If so that leaves a single point of failure for the pre-boil gravity reading. As others have mentioned, stir before taking your pre-boil gravity reading. But I think @Zambezi Special may be onto something. Do you adjust your hydrometer reading for temperature?

 

[Simonpyman]

I would assume you only used your tilt for the post-boil/fermenter reading. If so that leaves a single point of failure for the pre-boil gravity reading. As others have mentioned, stir before taking your pre-boil gravity reading. But I think @Zambezi Special may be onto something. Do you adjust your hydrometer reading for temperature?

I didn’t adjust for temperature, which makes that the likely reason for the off reading

 

[Minbari]

I didn’t adjust for temperature, which makes that the likely reason for the off reading

Really depends. Most hydrometer are calibrated @60F. Even 50F different is only a few pts.

With a refractometer, make zero difference. The 2drops cool instantly

 

[Zambi]

I figure the temp reading may get you out by 5 gravity points or so, but the boil should have a bigger effect
Do you have your start and end volume for us?

 

[Simonpyman]

I figure the temp reading may get you out by 5 gravity points or so, but the boil should have a bigger effect
Do you have your start and end volume for us?

Start volume was 7 gallons and end volume was ~ 6 gallons

 

[Zambi]

You should have come out at 1.058
So most likely still a combination of things.
But it will be beer

 

[Simonpyman]

You should have come out at 1.058
So most likely still a combination of things.
But it will be beer

Exactly haha! Fermentor has been happily bubbling away. Excited to taste this before kegging