Massive amounts of black malt...What's the worst that can happen?

Every ingredient seems to get this sooner or later. Stuff like peated rye and honey malt have had SMaSHes made, but I'm curious about black patent malt. What's the most anyone's ever used in a beer? I was thinking a 1 gallon batch, with either a small amount of 6-row to convert or using amylase powder to mash a true black malt SMaSH.

I'm really curious about other folks' experiences with high amounts of black malt, whatever variety, debittered or non, etc. Are there any surprises or depth in this malt, or is it pretty much going to taste like a fireplace no matter what?

There isn't anything in black malt to mash. Virtually all the starch has been carbonized. You will end up making very low alcohol charcoal water. But, hey, it's your beer.

I've used about 10% in a stout and it came out quite ashy and astringent. It's gotten a lot better with time. I'm 4 months in and its starting to round out with some chocolate coffee flavors but they still take a back seat to the ashy-ness.

In most recipes there is usually only a couple percent used so IMO anything more than that you will not be happy with the results. In fact it doesn't even need to be mashed, it can be just steeped to impart color.