Biggles

Recipes 

My local brew store uses Gambrinus malts and does actually carry Marriss Otter, but has an ESB Pale Malt, which is really similar. I just picked up the grains for my oatmeal stout, and when I got home realised that I have pale malt for base, not ESB pale malt (Likely my fault, since the names are so similar). Will this be a weird brew, or will it just not be as rich with the pale?
From what I understand, the Gambinus pale is 2-3L, and the ESB pale is 3-4L.

zachattack

Recipes 

Next time you're in the store, I'd suggest munching on some of the whole grains. It'll give you a great idea of the flavor.

I'm not sure what brands my LHBS stocks, but MO is much more flavorful than standard pale malt, and IME the ESB malt is somewhere in between. There will be a difference, but probably not huge in a stout since the roasted grains will dominate the flavor.

Biggles

Recipes 

That's what I figured. I Know what the difference between the two grains is like, and if I had to guess, then the pale will lead to a drier beer that's not quite as full. Since half the batch is getting a flavour addition in the secondary, I don't think it would be so bad. The specialty malts are 24oz oat flakes, 14oz Crystal 60L, 12oz Chocolate and 8oz of roasted barley, so they will definitely dominate.
The guy at the store was saying that the Gambrinus ESB is a good substitute for MO, but not having access to MO, I wouldn't know.
I'll brew it up, at the end of the day, I have beer, so it's not that bad