Adding Chocolate To Left Hand Milk Stout Clone

I'm planning on brewing a 5 gallon batch of an all-grain Left Hand Milk Stout clone and adding some chocolate to it. Should I use cocoa? How much should I add and when should I add it to the boil? I'd like the chocolate flavor to stand out.

Here is the recipe without the chocolate addition:

1 Pkgs California Ale (White Labs #WLP001) (Starter 900ml)
--
Prepare Ingredients for Mash
Amount Item Type
7 lbs Pale Malt (2 Row) US (2.0 SRM) Grain
1 lbs Roasted Barley (300.0 SRM) Grain
12.0 oz Caramel/Crystal Malt - 60L (60.0 SRM) Grain
12.0 oz Chocolate Malt (350.0 SRM) Grain
12.0 oz Munich Malt (9.0 SRM) Grain
10.1 oz Barley, Flaked (1.7 SRM) Grain
8.0 oz Oats, Flaked (1.0 SRM) Grain
2 min Mash Ingredients
Mash In: Add 14.23 qt of water at 166.1 F
75 min - Hold mash at 151.0 F for 75 min
-- Batch Sparge Round 1: Sparge with 3.94 gal of 168.0 F water.
-- Add water to achieve boil volume of 6.13 gal
-- Estimated Pre-boil Gravity is: 1.054 SG with all grains/extracts added
Boil for 60 min
Boil Ingredients
Boil Amount Item Type
60 min 0.35 oz Magnum [12.50 %] (60 min) Hops
60 min 1 lbs Milk Sugar (Lactose) (0.0 SRM) Sugar
10 min 1.00 oz Goldings, East Kent [5.00 %] (10 min) Hops

I made a clone of this beer last year and loved it.

If it was me, I'd up the amount of lactose in this a bit, and then add either cocoa powder or cocoa nibs after primary fermentation. The extra sugars for a little extra milky sweetness, and you want the chocolate to be an addition, not something that's boiled.

A couple of recommendations from doing chocolate stouts. If you want it to really taste like chocolate, you need to use a lot. If you want a subtle flavor use about 4oz. If you want a real chocolatey flavor you can use about 8-12oz. I've used up to a pound before and it was too much (but it was fun ) I haven't had that beer so I don't know how much chocolate flavor it has. If you use too much cocoa, the mixture will stratify in layers until you hit high krausen and then it'll kick up and mix it again. I find it's best to boil because it mixes it in real good. Also, be ready for the head this thing kicks up if you add it in boil. I would save your money on the fancy nibs and expensive powders. I did that and it really wasn't worth the cost for the return. Get quality chocolate, but don't break the bank on it. Use a blowoff tube.

Thanks for the information. Interesting that I got a mixed response on when to add the chocolate. I was originally thinking of adding both a pound of lactose and a pound of cocoa powder about 15 minutes before the end of the boil. Any recommendations on what type of cocoa to use? Would Hersheys be okay or should I try to find something else?

A pound will definitely get the job done. I had a lot of it stick to the kettle, wort chiller, etc after the boil was done so it saturated almost completely, which is why you could use less and save money. I haven't used Hershey's but it should work fine. I found some stuff at the farmers market sold in 1lb and organic that I believe was also cheaper so I used it.

One other thing to mention is that if you are looking at using different cocoa powders, there are basically two types. There's natural cocoa and alkalized cocoa (called dutch processed cocoa). Aside from color and flavor differences, the second type would increase your pH. I'm not sure how much a pound would increase the pH on a large scale of 5 gallons, but be aware.