Are New Mexican green chiles seasonal?
Hatch green chiles are all the rage and it seems like the season is upon us. What gets used the rest of the year? Are there other growing areas that come into season at different times in the Southwest? Do restaurants just stock up by roasting and freezing? I had some great green chile in Deming at the end of March. Where are the chiles coming from during the rest of the year?
I live in NM where green chile seems to be on the majority of restaurant menus (including McDonalds, Sonic, etc.), and here at least, most restaurants get locally roasted chile from around Hatch and freeze for the year. It freezes and thaws very well, and I've never been able to tell much of a difference between the in season vs. the frozen. There's definitely a range of quality; in my experience you've found a good batch if the pieces of chile are irregularly cut, have some char marks, and sport the occasional tinge of red.
CO, AZ, CA, west TX, and Mexico all grow their own green chile. A lot of people in NM claim that the terroir around Hatch stands its chile head and shoulders above anywhere else; I'm not enough of an expert to really have an opinion. Regardless, there are a number of protectionist in-state campaigns to "keep New Mexico green" and only source local green chile, and NM's usually amicable relations with Colorado periodically get a little testy when CO publicly touts its green chile over NM's.
I don't know if restaurants store a whole year's supply or if they buy periodic wholesale batches (presumably it varies from restaurant to restaurant), but it'll definitely be frozen. The chile harvest is late summer only; the lowest point in NM is about 2800 feet, so we have winters despite being so far south.
As for home cooking, lots and lots of people in NM have chest freezers to store their personal chile stashes for the year. Each August or September you buy a 50 lb sack of green chile at the grocery store, get it roasted in the parking lot (chile roasters look like giant bingo tumblers with propane jets at the bottom), divvy it up in to whatever size bags you find useful, and freeze until needed. Every late summer you'll see ads in the paper for sales on chest freezers.
There are a few stores and restaurants in NM that import the same variety of chile they grow in Hatch from Mexico and get periodic deliveries year-round. I think that's what a lot of restaurants do in NYC and other places where freezer space is at a premium. Pro's Ranch Market, for example, a large Mexican grocer in Albuquerque, roasts chiles two or three times a day all year. If they're not from Hatch, NM, a business is not supposed to call them Hatch green chiles, but I think a lot of places outside NM do that anyway.
As finlero says, most people here buy a huge stock right about now and freeze a supply for the year. I'll be doing that next week-end. This year Wagner Farms in Corrales has some of the best roasted green chile I've ever tasted.
They seem to be popular here in Arkansas when the season hits. And at least one store is roasting them in the parking lot in a kind of tumbler (like you might pick a lottery ticket out of) over open flame, then bagging and selling them that way as well.