Efficiency question

[timboslice1982]

This weekend I brewed a pumpkin ale based on Midwest Supplies all grain pumpkin kit. Fermentables consisted of:

9 lb - 2-row
8 oz. - Carapils
8 oz. - Crystal 10L

The post boil gravity was 1.044 for a 5 gallon batch. Every efficiency calculator I tried gives me an efficiency ranging from 59%-63%. Manual calculations support this using PPGs both from Palmer and the chart on this site. My estimates were roughly 1.054 at 75%

My question is this - the recipe sheet gives an SG (post boil) of 1.042-1.046, and Midwest says they calculate for 70% efficiency at 5 gallons. According to them I'm right on, but everything else I see says my efficiency is lower.

What gives?

 

[MichaelBrock]

Beersmith, for a 5 gallon batch (which, with my equipment & a 60 minute boil, means 6.1 gallons pre-boil) and that grain bill gives an estimated pre-boil gravity of 1.043. What was your pre-boil volume?

 

[timboslice1982]

Pre-boil volume was 6.5 gallons with at 1.034.

 

[MichaelBrock]

Somehow, I misread your original question. Reading "pre-boil" where you had "post-boil". Beersmith estimates an OG of 1.051 @ 70% efficiency and 1.055 at 75%. So it matches your estimate. That said, Beersmith estimates a pre-boil gravity of 1.046 at that efficiency. If you measured 1.034 in 6.5 gallons of wort (which is 60% extraction efficiency) you should have ended up with an OG of 1.045 at 5 gallons; that matches your measured OG. So the evidence seems to suggest that you really did get 60% efficiency. And also that Midwest's recipe sheet is wrong.

 

[GotPushrods]

9 lb - 2-row
8 oz. - Carapils
8 oz. - Crystal 10L

The post boil gravity was 1.044 for a 5 gallon batch.

Let's just work through it. It's a simple problem.

We have all base and light crystal malt. It is safe to assume 36 PPG for all 10 lbs. 10 lbs * 36 PPG = 360 total points. This is 100% and all you can hope to get.

You ended up with 44 points * 5 gallons = 220 points of delicious sugars.

220 / 360 = 61%.

Of course this assumes 100% conversion efficiency, which I think is fair given fresh malt from Midwest. You would need to take a gravity of the mash to know for sure.

I'd say the recipe sheet has a typo.


EDIT: Although, where does the pumpkin come into play?

 

[timboslice1982]

Thanks for the replies everyone! I've been banging my head against the wall, convincing myself I had miscalculated. Hopefully the beer will turn out and I'll know now to just stick with running my own numbers instead of trusting pre-calculated values for a recipe.

 

[bxtzd3]

I did a pumpkin ale as well and I had 7 points lower the suggested, for pre and post. I used three cans of pumpkin in the mash. I think it doesn't account for the added ingredient. the pumpkin has to take something away.