Which beer items does he take for the achievement?

not sure what you mean? For him appearing all you are doing is looking for rats in the Galley, which doesn't involve you having anything in your Inventory. For the drinking game, I'm pretty sure you need hard liquor like absinthe/brandy/whisky and not beer.

There's also a Drunk Gunter achievement: Give 150 beer items to Drunk Gunter!

That uses any item with the word "beer" in it, but I don't think you can access drunk gunter unless its alegarten.

The liquors were not working for the achievement. It has to be beer items. I wasted about 100 absinthe before learning that the hard way haha.

He would not take I was able to get to him by going to the Subetapedia and clicking on Holiday NPCs. I gave him about 100 absinthe before realizing it did nothing for the achievement LOL. Then I bought 5 free beers and he did not even recognize those,lol.

You are not making any sense to me. Typing "matty" into Achievements gets you an Achievement that doesn't involve any kind of liquor at all. There is no link there. Dirty Matty Achievement doesn't ever happen on the Dirty Matty Drinking Game under any circumstances whatsoever no matter how much you play that game or what liquor you use. It doesn't occur by feeding alcohol to Matty. There is an Achievement for feeding beers to Gunter, another NPC entirely. Gunter doesn't drink any absinthe and isn't named Matty.

.This Achievement that I could find by using the word 'matty' happens in Angrybeard's Galley. You are hunting for rats, and get items as rewards most times. However, sometimes instead of a rat, you get a Wyllop.

Okay, I see what's going on.

The achievement you are thinking of is the Drunk Gunter achievement - that's the one that takes "beer" items. It is only available during Alegarten in October.

The link you are going to is the Dirty Matty's drinking game, where he takes hard alcohol. There is NO achievement for this game. All you get is what you win when he passes out.

Yall are right. Well I feel completely stupid now,lol. I have no idea why on earth I mixed Gunter up for Dirty Matty. Thank yall for clearing that up for me though :)

you are welcome

Not stupid - easy to get confused. LOL beer is alcohol too! So many achievements, bits and pieces stick in our minds, its easy to mix them up :)