[denny]

Double IPAs finish at a higher gravity than IPAs because they have a higher original gravity. I myself like to add a little sugar to DIPAs so they don't finish too sweet. I wouldn't worry too much about your terminal gravity being too low, especially if you don't add any sugar.

As far as your hop question, I found Ahtanum to be somewhat underwhelming when it first came out. Amarillo would be a decent substitute, personally I would use a mix of Centennial and Amarillo for flavor and aroma additions. As far as Millennium, that's a bittering hop. I would probably use Warrior as a substitute. Magnum would be another good choice. Your suggestion of Nugget would work, but you probably would have to double the quantities.

This is super helpful. Thanks,
I thought yeast strains were developed to always hit the same FG (not repitch), do they instead work within a range of points or something?

On doubling the quantitues, my nugget hops have a 14.8% AA and the Millenium data I found lists 14.5 - 16.5 so isn't that pretty close enough?

A yeast strain may list an attenuation %, but that's not FG. And even attenuation % can vary depending on the wort. That's why you want to use sugar in a DIPA.

[denny]

Sugar is definitely needed for DIPA to distinguish from BW

Hmm.. Any rule of thumb as far as percentage of sugar to grist?

At least 5. I usually go 10. I've started using 5% in all my "regular" IPA.

[Joe_Beer]

At least 5. I usually go 10. I've started using 5% in all my "regular" IPA.

Perfect! Thanks again.

[Joe_Beer]

At least 5. I usually go 10. I've started using 5% in all my "regular" IPA.

Do you scale back the grist accordingly then so your ABV isn't off the hook?  I'm kind of adding the sucrose to Brewfater after I've already scaled the recipe down.

[goose]

At least 5. I usually go 10. I've started using 5% in all my "regular" IPA.

Do you scale back the grist accordingly then so your ABV isn't off the hook?  I'm kind of adding the sucrose to Brewfater after I've already scaled the recipe down.

Yes, you can scale the malt bill back a bit but try to make the IBU's to OG numbers match somewhat closely so that you keep the beer relatively balanced.  I use Beer Smith and there is a graph of gravity numbers to IBU number and I keep the arrows on the graph close and also shoot for the middle of the style guidelines range of both.  But, it's your beer, make it they way that works for you.

I assume you are adding the sugar to the kettle, just to verify.  I also use dextrose (corn sugar) instead of sucrose in the kettle.  The only time I use sucrose is when I make a Tripel, but you can do what works for you and what you have on hand.

[denny]

At least 5. I usually go 10. I've started using 5% in all my "regular" IPA.

Do you scale back the grist accordingly then so your ABV isn't off the hook?  I'm kind of adding the sucrose to Brewfater after I've already scaled the recipe down.

Yeah, I do.

[Joe_Beer]

Yes, you can scale the malt bill back a bit but try to make the IBU's to OG numbers match somewhat closely so that you keep the beer relatively balanced <snip>

I assume you are adding the sugar to the kettle, just to verify <snip>

Ok, good. That's about the path I took (heating up to boil right now). In Brefather, I'm over OG by just a hair (10.1), and IBU is 89 now. I backed off the main malt to bring the OG down and then added a little extra caramel malt to get the SRM back.

Yep, just using sucrose. I know dextrose is popular too, but I could never find a compelling reason to switch over. I think just having yet another ingredient I needed to purchase kept me using sucrose.

Yeah, I do.

Ok, thanks for clarifying