Low Gravity, High pH

[blackstrat5]

Tried making a pumpkin ale yesterday aiming for 1.081. It came up as 1.056 rather (added DME to the boil to correct for the low gravity). The volumes were all correct (came up with the correct final volume, trub loss and pre-boil).

I used Beersmith to come up with Strike volume and temps. It was set for a 70% effeciency and a grist ration of 1.75. With around 15 lbs of grain, at that ratio the sparge was a little less than two gallons. (I did sparge with 170 F water). The grain was milled at my LHBS and is usually fairly consistent in crush.

The mash pH was 5.8 at a temperature of 156.

I know that's not a target pH, but could that really be the cause of the poor extraction? Or is the really low sparge volume the cause?

 

[Pie_Man]

Low sparge volume and high pH can certainly lower efficiency. What was your grain bill?

 

[BOBrob]

How did you measure PH, meter or strips, wort hot or cool and when? After conversion? I normaly use around 4 gal. to sparge. Thats a lot of grain to wash with 2 gals. You may have left a lot of sugars in the grain bed. Just thinking , I would strike with 4.5-5 gals. & sparge with around 4gal. or more to get what I needed for 5.5 gal. in the Ale pail. The LHBS are not well known for a good crush, so the efficiency will hurt. Before I got a mill; 60% eff. was high with a store crush. If you dont have access to a mill, use a rolling pin and crush the store s crush even more. It is work,but it helps. Good luck

 

[blackstrat5]

Bill:
13.6 lbs 6-Row
1 lb Crystal 20
1 lb Victory
0.25 lb Crystal 90
3 lbs of Pumpkin

Now that I've put that down I'm wondering since BeerSmith calculated the 3 lbs of Pumpkin as Grain as part of the 1.75 qt/lb grist ratio. But I would think with a thinner mash like that (still wouldnt be near 2.5 qt /lb) would help the conversion.

I used a pH meter on a cooled sample taken from the sample at 10 minutes. The crush from my LHBS seems to be fine before. I've used to get 72-76% effeciency from them before.

With that 1.75 grist ratio and given that the pumpkin was used in the strike volume calculation, I should have used a lower grist ratio like 1.25 or 1.5 qt/lb. Even though the thinner mash should have helped conversion effeciency the lack of a good sparge cut the overall effeciency of the mash?

 

[Pie_Man]

I think I thicker mash and more sparge water might helped in this case. While the thinner mash may have helped in conversion, the lack of sparge water may have left a lot of sugars behind. There's almost 19 pounds of grain and pumpkin with only 2 gallons of sparge water.

Also, what assumptions did you assign pumpkin in beersmith? If you have it set to the beersmith defaults, you probably over estimated the gravity potential of the pumpkin as pumpkin has very little sugar, https://www.homebrewtalk.com/f84/pumpkin-beersmith-262255/.

 

[blackstrat5]

I had Pumpkin set for 1.005 potential extract.

I guess I'll need to brew this again soon and see with a thicker mash and a higher sparge volume, the gravity can be corrected.