Really low gravity

[tominsj]

My Brother and I made a batch of Pumpkin beer for the holidays, this was our second batch. The last one we made we were a little low on the gravity, 10.5something as opposed to 10.60. We made a second batch using a little less grain and way more pumpkin, also we put about a pound of brown sugar in the first one and no sugar n the second.

This second one we figured to hit 10.50 or so, but in fact we got 10.32ish.

We did a step mash, 3.5 gal at 134 for 20 min, then an additional 6 gal at 154, same as the first batch, only different water volume last time but it was proportional.

Did a 60 min boil both times, and in the first batch we probably should have boiled for a little longer, which is probably why we didn't hit our gravity.

Anyway, we pitched the yeast figuring we could just make a session pumpkin to go with our stronger one.

Any ideas what might have gone wrong?

[spiderwrangler]

Couple of questions to help with clarifying. Assuming you are talking specific gravity, so 1.050 when you say 10.50? Were you using 9.5 total gallons in the mash? What size brew are you doing? Did you sparge after that, and with how much water? What was your amount of grain and ratio to water? I'm assuming you didn't take a gravity reading preboil?

[edisonst]

You get very little gravity out of the pumpkin, something like 5 # pumpkin equals a pound of malt. That said, if you didnt put sugar in your second batch and just bumped up the pumkin you would be losing gravity points. Ive been working out a pumpkin beer and the pumpkin contributes very little in the mash as far as sugar is concerned. Pumpkins potential is like 1.003 ppg wich is nominal.

[tominsj]

Sorry yeah, I get so used to saying ten fifty I put the decimal in the wrong place.

Anyhue, my water ratio was 1 quart per pound for the first infusion, so that was 3 gallons, may have been a little over, and 1.25 per pound for the second, so 3.75 for the second. And did a batch sparge with about 3 gallons, I stopped when the wort coming from my mash tun tasted a little grainy. Sadly, no I did not do a pre-boil gravity reading (something I need to add to my process, I just forget to sometimes). I figured I would boil until I hit my target volume.

The final volume I was shooting for was 5.25 Gallons, making a 5 gallon batch, as I usually lose about a quarter gallon in the transfer from boil kettle to fermenter, then from primary to secondary.

I wasn't counting on the pumpkin giving me much fermentable sugar, but I did have a lot of pumpkin material in my wort and un fermented beer.

[spiderwrangler]

I'm not real familiar with step infusions, but with 1 qt/lb and 1.25 qt/lb, that would put you at 2.25 qt/lb during your sacch rest, correct? That may be a bit on the high side, whether it's enough to reduce your efficiency enough to result in the low gravity you ended up with I don't know. The thinner your mash, the more water there is separating the enzymes and starch, so it will take longer to get the same amount of activity done. If you are batch sparging, if it was well mixed, there shouldn't be a big change in the runnings, it should be fairly uniform throughout.

[tominsj]

Thanks for the input, I will think about trying to get a thicker mash next time!