Papazian Imperial Stout; What went wrong?

Hello,

First, sorry for my English. If you have any question because I'm not clear, do not hesitate!

So, I brewed Papazian armenian imperial stout with some changes. I wanted to do a Chocolat Imperial Stout without going only with extract (I did a shortcut by using a kit). To get the chocolat taste, I tweaked with this recipe https://www.homebrewtalk.com/f68/dark-chocolate-stout-136707/

So here is what I used:

1 -English bitter kit
1lb Chocolat malt (papazian recipe called for 1/2lb black patent)
1/2lb Roasted Barley
2.6lbs DME (Papazian recipe called for 3.3lbs LME)
12oz lactose (10 minutes)
8oz cocoa (5 minutes) - it was pure cocoa no additives almost no fat
2oz Galena (60 minute)
1oz Target (2 minute)
2 packets Saf-04

So, I steepe at 155 for 30 minutes. Then I brough the grains to 170, sparge and brough the wort to a boil. Then I add 1/3 of the DME, the 60 minute hop and I put the rest of the DME at 15 minutes left.

I was expecting an OG of 1.075 as Papazian recipe called(I know, a little low for an Imperial) but I only achieve 1.066 (wort was at 71 degree).

So, next time Ill try an "All extract" recipe (no kit) or Ill wait until I get the equipment to do a partial mash. But, as of now, I only want to know where I miss the target to get a "low" OG like that. Im ending with a strong chocolat stout (that Ill anjoy) but If I made a mistake that I can avoid next time, Ill realy appreciate you to tell me!

Also, I put 2 packet of dryyeast because I was expecting a higher OG and, as I was over 1.060, I decided toput them anyway. Have I overpitch?

Thanks for your help!

A couple questions:
1. How much extract was in the English Bitter kit? You added the other ingredients to the English Bitter kit, is that correct?
2. What was your batch volume?

Forgot about that,

My boil volume was 2 gallon and I added the English Bitter kit (coopers 3.7lbs) at 15 minutes left to the boil. I ended out with 5.3 gal (20 litters). I know that its .3 gallon more than Papazian recipe ...

First, it's common with partial boil beers to have an inaccurate gravity reading. When you add water to bring the reciple to its full volume, the liquid have to be mixed together extremely well for the sugar solution to be equally dispersed and give an accurate reading.

Calculating the OG of extract beers is pretty straightforward. The extract has an estimated amount of gravity points per weight (varies by manufacturer, etc.) that can be used to determine your OG. For instance, LME has about 36 points per pound per gallon and DME about 40 (http://www.howtobrew.com/section1/chapter3-4.html), lactose is about 42.

In your case:

(3.7 lbs. of LME x 36) + (2.6 lbs. of DME x 40) + (.75 lbs. of lactose X 42) = about 269 total gravity points. Divided by 5.3 gallons = about 51, which equates to 1.051 OG.

This calculation is quite different than your measurement. Are you sure your volumes are correct?

You've tweaked the Papazian recipe a lot, so I wouldn't use that as your reference point. His recipe called for 3.3 lbs. of light DME (you used 2.6), his recipe also called for 6.6 of Munton's hopped LME (you used 3.7 lbs.). Also, different hops, different yeast, and different specialty malts.

hmmmm

you're right about the LME (3.7 vs 6.6) that should have an impact. The recipe called for 3.3 of "plain light malt extract syrup" so, to convert to DME, I just did 3.3x80%= 2.7lbs.

you're also write about the speciality malt and finishing hop... Ill use your calculation next time... In fact I'm shoping for a brewsoftware rightnow,.. I wont do the same mistake twice!

For what I understand, I also overpitch,...

Thanks

Don't worry about "overpitching", it's really almost impossible (within reason!). You'll be fine.