Crystal Malt Substitutions 80L vs 90L

After 2 partial mash brews I'm getting together ingredients to do my first all grain brew (jgourd's black IPA) next week and I ran into a slight snag, my LHBS has 60L, 80L, and 120L crystal malts but the recipe calls for 90L. Should I just go ahead and use the 80L? Is there that big of a difference between it and 90L?

Sorry if this have been covered before, I did a search but the results were people discussing far more drastic substitutions like 70L for 20L.

80L will be fine. Plus...you don't have much of a choice!

Yeah i mean if it were going to make a huge difference I'd order the 90L online (no sense in going through all that work and screwing it up with a little detail) but if it's not going to change things too much I'll just go with the 80L

I run into this same problem almost every brew. It's not a big deal. Sure, a 10L difference will theoretically make for a darker beer but I doubt anybody would ever be able to tell. Just get what's closest and go ahead as planned, your beer will be just fine.

My LHBS says the stuff he gets in is always marked for a range. Think plus/minus. I doubt any of the stuff is dead on.

80 is close enough to 90, but it's not just the color with crystal malts, the darker grains will have a different flavor as well. IOW, you can't use 8 oz of 40L to substitute perfectly for 4 oz of 80L.

The difference in flavors from one maltster to another will probably be greater than the difference between a given maltster's 80L and 90L crystal.