Three breweries in Vermont are generally regarded as three of the best in the USA, if not the world: The Alchemist, Lawson's Finest Liquids, and Hill Farmstead Brewery. With a couple of exceptions, this guide totally focuses on them.
The Alchemist (Waterbury, VT)
At the moment, The Alchemist REGULARLY produces only one beer -- Heady Topper, a canned double IPA generally considered as one of the best beers in the world and is number one on the BeerGraphs leaderboards. The brewery is no longer open to visitors for a variety of reasons. However, you can purchase the beer to take home with you at a lot of locations. Deliveries are made to these locations all five days of the week -- you can find a detailed rundown of when deliveries are made here. It generally sells out VERY rapidly at all of these stores -- it's hard (although not impossible) to find fourpacks to go on weekend days. However, you can find it on draft/in cans at bars pretty easily -- I discuss this later.
The Alchemist also recently has been canning one-off batches of other beers and releasing them at special "can release" events in Waterbury on Saturdays. These are few and far between -- check the Alchemist website for details.
Lawson's Finest Liquids (Warren, VT)
Sean Lawson is essentially a home brewer licensed to sell bottles of beer. He has no brewery that you can visit (and no growlers), and the beer is sold in bottles only at three stores: Warren Store, in Warren, Hunger Mountain Coop, in Montpelier, and Beverage Warehouse in Winooski. Deliveries are on Thursdays at the Warren Store and Beverage Warehouse, and on Fridays at Hunger Mountain Coop. The beer, as with Heady Topper, sells out very, very fast. Generally, bottles are gone from stores the same day they are delivered. The Warren Store gets the most bottles, but is the biggest pain to get to. Hunger Mountain Coop is the easiest to get to - bottles are delivered at 3:00 PM on Fridays (the same time cases of Heady Topper are delivered there) and will likely be gone in an hour.
The only other way to buy bottles to attend a farmer's market he sells beer at. These are roughly monthly and are announced/described on his blog.
Hill Farmstead (Greensboro Bend, VT)
The only place I recommend for a visit - but definitely a major, major pain to get to.
Probably not a stretch to say that Hill Farmstead is generally regarded as the best brewery in the USA, if not the world.
Beer is sold in bottles/growlers only at Hill Farmstead -- in a very rural (but pretty!) area, and will require some dirt road driving. Open 12 PM - 5 PM, Wednesday through Saturday only. They take cash only (although this should be changing soon). There is no ATM on site -- bring a LOT of money, you will want to spend it.
Saturdays are generally a mess. They open at 12, and it is not unusual to wait more than two hours in line for growlers if you show up at say, 12:30. Last time I was there, I arrived at 11:15 on a Friday (read: 45 min before opening) and there were approximately 40 people in line in front of me. While you wait in line for growlers, you can do a tasting -- four small glasses of beer for $5.
If you don't want to wait in the line, you can go in the "bottles only" line which has no wait, generally, as the bottles are prefilled, unlike growlers, but the IPAs/other hoppy beers are available only in growlers.
As I understand it, if you were to arrive more like 3 PM, you might not have to wait in a line, but I generally would prefer not to risk that, myself.
Their website has a completely up-to-date list of whatever is available at the retail store at any given time.
If you have growlers, bring them -- Hill Farmstead will fill regular 64 oz brown growlers from other breweries as well as their own. They will fill some other growler types from other breweries as well, but not many (e.g., not metal growlers) – a full policy can be found here.
So... that's a lot of discussion of a lot of places far away/hard to access/hard to get beer at on a weekend day that you will likely not go to. However, there is a saving grace, if you're just interested in drinking some good beers:
Some of the greatest beer bars anywhere in the Northeast are also in close proximity to these three brewers. Prohibition Pig, Blackback Pub, and The Reservoir are all in Waterbury, and literally less than 100 feet from one another. These bars typically have Hill Farmstead/Lawson's Finest Liquids on tap - Prohibition Pig also typically has Heady Topper on tap. They'll also usually have cans of Heady Topper to drink there, as well as sometimes kegs of the special Alchemist beers. Blackback is in transition at the moment and does not have food. The food at Pro Pig is really great. I've never eaten at The Reservoir, but heard the food there is good as well.
Three Penny Taproom in Montpelier is also on the way (~15 min from Waterbury) and also usually has The Alchemist/Lawson's/Hill Farmstead, as well as other GREAT beers, and really really good food.
Granted - there are a lot of other good breweries in Vermont! Switchback, Rock Art, Von Trapp Family Lodge, Bobcat, Otter Creek, Lost Nation, Zero Gravity, Magic Hat (although my feelings about whether Magic Hat is good or not are rather divided). But these three above are the ones the beer geeks go nuts about.
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