I'll be in Riverhead for my brother's wedding for a few days starting next week. I'm hoping to hit Hops 'N Vines, Tweeds, and a couple other places including a brewery or two. What I'm wondering if is anyone would want to meet up for lunch and beer one of those days and if there's anything I can get here in Ohio that someone might want me to bring with me. I'd love to do an in-person bottle trade or some sort of thing if anyone's interested.
Unfortunately your visiting during the week and most breweries here are open on weekends. I believe Port Jeff Brewing company is open during the week. They have some really good beers but from Riverhead its probably 30-40 minutes trip there. Mustache is really good and they may be open when you come on Monday for a few hours. Bottle shops I'd recommend Bellport Beer.. its a little south of you but its worth it. If your not worrying about travel try making it out to Superstar Beer in North Babylon or Huntington Station.
PJKelly82 is right that your best bet for a brewery will probably be Port Jeff Brewery, which is in Port Jefferson. While you're there you might as well stop off at Brewtopia of Long Island because while they don't have a large number of beers they curate a nice selection of Long Island breweries. And Brewtopia will certainly be a pleasure if you are a home brewer. Another stop that might be worth your interest is Patchogue, it might be a little closer to Riverhead then Port Jeff,as they have three craft beer bars and a couple breweries of their own. Blue Point Brewery can be found in Patchogue but will be closed the days you mentioned. Brick House brewery is there, but to be honest I find there beers to be nothing special. The reason to go would be for Hoptron Brewtique, BobbiQue, and The Tap Room between the three you will easily find a ton of local beers that you will love. Lastly, I didn't bring up Riverhead itself. Riverhead is home to three breweries Moustache, Long Ireland, and Crooked Ladder. Moustache from my understanding, and please someone correct me if I'm wrong, is only open on Saturdays. That's because they have such a small barrel system and so much support from the community especially since they just opened a month ago. I don't know what your travel arrangements are but Long Ireland will be open on that Thursday and if you can go I'd say do it along with Crooked Ladder since it's so close. Otherwise, I would pass on crooked ladder.
Just because you asked. Moustache has added brewery hours and is now open for at least a few hours Fri-Mon. Friday and Monday 3-7. Saturday and Sunday 1-6. They do seem to be playing catch up at the moment due to the support they received when they opened. The past couple of weeks they've only had 2-3 beers on tap, for pints of growler fills. And just to be nit-picky, Brewtopia (for some reason) is now known as the Port Jeff Hop Shop. No idea why, but noticed their rebranding recently.
Get the wings from Jerrys next to the hotel/aquarium in Riverhead...jus sayin... KornWallace - give Brickhouse another try if you have not been since Novemberish, new brewmaster I met last weekend and they are trying to really turn it around with alot of new recipes
If you go about 25 minutes East into New Suffolk you can hit Legends. They normally have 8-10 local craft breweries on tap and are open weekdays. Excellent seafood as well. The town itself is tiny, but the place is pretty cool. I'm there a few times a month, but only on weekends. My parents live around the corner.
I am actually free that week and if you are looking for anything from western LI, I'd be willing to travel to trade for some beers that we can't get here, especially if there is going to be any sort of swell in the water during that time (I love to travel to eastern LI for a good surf to switch it up from the typical western LI surf we get).