Missing OG and target volume

[Tand]

Hi all,

Completed my second All-Grain batch today but was short on the OG, and the volume in the fermenter, are they connected?
The grain bill was:
Targets: OG 1.068, FG 1.016, 6.9% ABV, 5.5 Gallons

11.5 lb Maris Otter (3L)
1.5 lb Vienna (3.5L)
12 oz Crystal 60 (60L)
8 oz Black Patent (500L)
8 oz Chocolate Malt (350L)

My pre-boil volume was 7.8 Gallons (large due to figuring out equipment profile), with a gravity of 1.050. After a 60 minute boil, I was able to transfer 4.8 Gallons - I would have gotten more but my pick up tube blocked, there was a huge amount of hop debris, and I was nervous about infection (outdoor brewing). However, after taking a gravity reading, I appear to have an OG of 1.056. I went ahead and pitched a 1L yeast starter ((WLP007), which after a couple of hours is already starting to bulge the fermenter lid!).

Can the difference in volume really account for such a difference in gravity(s)? And is there anything I can do, like adding DME, to remedy the situation?
Also should I attach a blow off tube?

Cheers brewers
T

 

[kev211]

Something sounds fishy here. How much total were you left with after the boil. I know you said you transferred 4.8 gallons, but how much was left in the kettle after that? Going from 7.8 gallons to 4.8 you should have had an O.G. closer to 1.07 with a pre-boil of 1.05 so something is off.

Also, I wouldnt worry about the hops going into the fermentor. Many people dont like the trub to go in for volume and other reasons but you wont get an infection from hops (usually) especially not boiled hops.

And why is your fermenter lid bulging? Do you not have an airlock or blow-off?

 

[Tand]

Something sounds fishy here. How much total were you left with after the boil. I know you said you transferred 4.8 gallons, but how much was left in the kettle after that? Going from 7.8 gallons to 4.8 you should have had an O.G. closer to 1.07 with a pre-boil of 1.05 so something is off.

Also, I wouldnt worry about the hops going into the fermentor. Many people dont like the trub to go in for volume and other reasons but you wont get an infection from hops (usually) especially not boiled hops.

And why is your fermenter lid bulging? Do you not have an airlock or blow-off?

In a rush to clean up I didn't measure what was left in the kettle so would have to guess... it was maybe at a gallon? Not good, I know, but other things around me forced my cleaning hand.
I thought that a reason the gravity may be low is due to not mixing the wort once transferred, but I then thought that was only a real issue for extract due to dilation.
Bulging, but not yet enough to engage the airlock I guess?

 

[kev211]

In a rush to clean up I didn't measure what was left in the kettle so would have to guess... it was maybe at a gallon? Not good, I know, but other things around me forced my cleaning hand.
I thought that a reason the gravity may be low is due to not mixing the wort once transferred, but I then thought that was only a real issue for extract due to dilation.

Im thinking it was that the wort wasnt mixed. Ive had that issue before on AG. Actually just a few brews ago I had a 1.080 beer come in at 1.050 and once I mixed the wort I was at 1.079. So I think you may have not "mixed" it enough.

You have two options at this point. Just say screw it and let it ride, or take another gravity sample asap before fermentation really gets going. But if you do that, SANITIZE

 

[Qhrumphf]

Poorly mixed wort is seldom an issue after a full boil. However, it's very much an issue for pre-boil gravity. Even losing a gallon to hops, your preboil reading would put you at 1.067 after the boil. Either your preboil reading was wrong (possible) and your efficiency was very poor (would look to grain crush first), or you left behind even more than you think you did. I'd assume the latter, as boiling off 2 gallons in an hour, let alone 3 gallons, is quite a bit. For your preboil and postboil gravities to line up, you'd need 6.9 gallons after the boil. Boiling off a gallon in an hour (7.8 to 6.9) is a little closer to what I would normally expect from normal boiloff.

 

[Tand]

Poorly mixed wort is seldom an issue after a full boil. However, it's very much an issue for pre-boil gravity. Even losing a gallon to hops, your preboil reading would put you at 1.067 after the boil. Either your preboil reading was wrong (possible) and your efficiency was very poor (would look to grain crush first), or you left behind even more than you think you did. I'd assume the latter, as boiling off 2 gallons in an hour, let alone 3 gallons, is quite a bit. For your preboil and postboil gravities to line up, you'd need 6.9 gallons after the boil. Boiling off a gallon in an hour (7.8 to 6.9) is a little closer to what I would normally expect from normal boiloff.

So what do you think my options are at this point?

 

[GilSwillBasementBrews]

I would just let it ride and chalk it up as learning experience to take better measurements going forward ( gravity and volume both) and not repeat previous errors. Distracted brewing seldom results in the beer we set out to make lol. Think we've all been there. But to answer you original question I'd say no to your gravity being off that much by not properly mixed wort. As Qhrumphf stated if you had 7.8 gallons at 1.050 you'd have to boil down to 6.8 gallons to hit your 1.056 OG. If you did boil down to 4.8 gallons your gravity should've been around 1.081

 

[Tand]

I would just let it ride and chalk it up as learning experience to take better measurements going forward ( gravity and volume both) and not repeat previous errors. Distracted brewing seldom results in the beer we set out to make lol. Think we've all been there. But to answer you original question I'd say no to your gravity being off that much by not properly mixed wort. As Qhrumphf stated if you had 7.8 gallons at 1.050 you'd have to boil down to 6.8 gallons to hit your 1.056 OG. If you did boil down to 4.8 gallons your gravity should've been around 1.081

Hmmm, so do you think it's a mis-measurement, or I left more than I thought in the kettle?
I'd quite like to get it up to the proper OG, is adding DME or invert sugar an option? Could I wait until fermentation looks complete and then add sugar?

 

[GilSwillBasementBrews]

Yeah I'd think there was more in the kettle than you thought. Yes you could bump up the gravity with some dme or sugar. I think I'd use dme over sugar though as sugar will ferment complete and dry the beer out some as well.

 

[Qhrumphf]

Adding DME is an option. Another is brewing a high gravity version and blending them.

 

[vance]

Piggybacking off this thread - how is everyone measuring volumes in their kettle? I tried the battery etching method but it didn't work so I still have no good way to estimate my boil loss and post boil volume.

 

[Blurryface]

Was the gravity reading taken with a refractometer or hydrometer? If hydrometer did you adjust for wort temperature?

 

[Tand]

Was the gravity reading taken with a refractometer or hydrometer? If hydrometer did you adjust for wort temperature?

Hydrometer. And yes, accounted for wort temp

 

[Qhrumphf]

Piggybacking off this thread - how is everyone measuring volumes in their kettle? I tried the battery etching method but it didn't work so I still have no good way to estimate my boil loss and post boil volume.

Nothing wrong with the good old dipstick method. Pour measured amounts, mark it on a stick as you go. Before I etched my kettle (worked wonderfully for me), I used an old plastic mash paddle that I'd outgrown.