Lower OG in partial mash

sfrisby · 03-07-2011, 12:41 AM

Will a partial mash recipe typically come up short in OG when a large part of fermentables come from extract?

Calculators estimated 1.12 and came in at 1.10. Was wondering if there can be that much of a spread with a big extract contribution?

Thanks.

**MalFet** · 03-07-2011, 01:31 AM

Certainly can, but you'd need to post a recipe and process (along with, ideally, a gravity reading from your mash before anybody will be able to say anything helpful to you.

**PurpleJeepXJ** · 03-07-2011, 01:39 AM

Typically extract recipes will come up short. No need to worry.

**MalFet** · 03-07-2011, 01:45 AM

Quote:

Originally Posted by PurpleJeepXJ

Typically extract recipes will come up short. No need to worry.

Huh? Why? I've never seen that.

**PurpleJeepXJ** · 03-07-2011, 02:03 AM

Because of the water used to top off not being mixed completely with the mash solution. Therefore the lighter top off water is on top of the heavier solution. Simple science... Am I wrong?

**MalFet** · 03-07-2011, 02:14 AM

Quote:

Originally Posted by PurpleJeepXJ

Because of the water used to top off not being mixed completely with the mash solution. Therefore the lighter top off water is on top of the heavier solution. Simple science... Am I wrong?

Sure. What you said here is correct enough, but that doesn't mean that extract has a lower gravity. It just means that there are wrong ways to take gravity on an extract batch, right? Without asking when and how the OP took his reading, it seems a bit premature to assume that's what happened.

**PurpleJeepXJ** · 03-07-2011, 11:55 AM

Ya you are correct

sfrisby · 03-07-2011, 07:27 PM

4lb Amber LME, 6lb Light LME, 2 lb Light DME

1lb 2row, 2 lb German Munich, 1 lb Crystal 40, 1/4 lb Special B

60 oz. canned pumpkin (baked at 350 for 30-40 min to carmalize), 1.5 oz. boubon, 1.5 oz wood chips, 6 cinn sticks, 1 1/2 tsp nutmeg, cloves, 1 oz. ginger (all secondary)

3 oz Mt Hood (60 min), 1 oz. Liberty (60 min), 1 oz. EKG (20 min)

Dry Nottingham yeast (2 packs, rehydrated)

No SG was taken until after top off water was added, but I shook that carboy like a 9.5 earthquake before I drew a sample for an OG. I really would be suprised if it wasn't mixed well enough. Really wanted to get some 02 in there for a beer that big.

**MalFet** · 03-07-2011, 07:36 PM

Quote:

Originally Posted by sfrisby

4lb Amber LME, 6lb Light LME, 2 lb Light DME

1lb 2row, 2 lb German Munich, 1 lb Crystal 40, 1/4 lb Special B

60 oz. canned pumpkin (baked at 350 for 30-40 min to carmalize), 1.5 oz. boubon, 1.5 oz wood chips, 6 cinn sticks, 1 1/2 tsp nutmeg, cloves, 1 oz. ginger (all secondary)

3 oz Mt Hood (60 min), 1 oz. Liberty (60 min), 1 oz. EKG (20 min)

Dry Nottingham yeast (2 packs, rehydrated)

No SG was taken until after top off water was added, but I shook that carboy like a 9.5 earthquake before I drew a sample for an OG. I really would be suprised if it wasn't mixed well enough. Really wanted to get some 02 in there for a beer that big.

Shaking, no matter how much of it you do, often won't properly mix water/wort layers. With a partial mash you generally want to take a gravity reading on your mash rubbings and then add extract to hit your numbers.

This was a relatively small mash, so to be off by twenty points you would have had to have very low efficiency for that to be the explanation. What is the gravity now, and how much yeast activity are you seeing? Like the other poster mentioned, my hunch is that it was just a mixing problem.

sfrisby · 03-09-2011, 10:07 PM

Moved to the secondary a couple of weeks ago, so now about 6 weeks old, so not much yeast activity now. Haven't taken a SG reading since moving to secondary. At that point it was 1.03 and was racked onto a yeast cake. Between that and the addition of a little sugar in the 60oz of pumpkin, I am sure it will finish out nicely. Just wondering what I could differently in the process to get a more accurate OG.

By the way, whats the highest OG you have come across in an extract?