Unexpectedly high starting gravity
I did my third partial mash brew yesterday (after many successful extract brews) and all seems good, except my starting gravity was much higher than expected.
Here's my recipe:
Type: Partial Mash
Batch Size: 5.00 gal
Boil Size: 3.50 gal
Boil Time: 60 min
Mash for 70 mins @ 150
2.50 lb Munich Malt
1.00 lb Wheat Malt
0.25 lb Acid Malt
Late addition (10 mins)
4.00 lb Light Dry Extract
1.00 lb Jaggery
0.50 oz Northern Brewer [7.40 %] (60 min)
0.50 oz Sterling [7.00 %] (30 min)
0.50 oz Goldings [4.10 %] (30 min)
0.50 oz Sterling [7.00 %] (5 min)
0.50 oz Goldings [4.10 %] (5 min)
1.00 items Orange Peel (Boil 5.0 min)
0.25 items Grapefruit Peel (Boil 5.0 min)
0.75 oz Coriander (Boil 5.0 min)
2.00 items Star Anise (Boil 5.0 min)
1 Pkgs Belgian Ale (White Labs #WLP550)
My two previous partial mash brews both ended up with 60% efficiency. I tweaked my sparge process a little this time in an attempt to improve that, but was expecting at most say a 10% boost.
But here's the thing - with 60% efficiency, BeerSmith predicted an SG of 1.060, but I ended up with 1.073!
How can this be? I'm not particularly worried about it (I'm sure the beer will still be good, if a little stronger than expected) but I'd like to understand what happened here.
Some things I considered:
- Bad gravity measurement? But I repeated this a second time, and got the exact same figure both times. Wort temperature was bang on 60 when I sampled it.
- My mash efficiency somehow went through the roof? I don't see how that could account for it, though: BeerSmith reckons I would only get 1.071 SG even if I somehow hit 100% efficiency!
- Bad measurement on some of the ingredients? The only one I can imagine getting my quantities wrong on here is the jaggery. But to explain that gravity, I would have had to use more than twice as much as intended. I don't see how I could have gotten that so far out.
Any other explanations I'm missing?