I learned the ways of canning salsa from a used-car salesman named Roy. He looks like Willie Nelson, bandana and all, and speaks with a southern twang thick enough to get your truck stuck in. He likes his salsa dangerously hot, and told me he once used habañero peppers as a poor man's methadone to help kick a drug habit. On a carefully planned September Sunday a few years back, with Mrs. Roy safely out of town, I went over to Roy's house. Football was on the tube, near-beer was flowing, and we donned hospital gloves, each of us out to make a year's supply of salsa.
In my case that meant about five gallons. I take my salsa in reasonable doses, with eggs in the morning and on corn chips after noon. On my own I'd be fine with five quarts for the year, canned in pint-sized jars. But when Shorty sits down, as she often does, with a spoon and a quart of my salsa, she'll slurp it away faster than you can say "buenos nachos."
Like Roy, I also like my salsa hot. Beyond improving the flavor experience, pepper heat triggers the release of endorphins similar to those responsible for runner's high and heroin's kick. Most importantly, the heat slows down Shorty, who would otherwise mainline my stash before the jars had even sealed.
In my experience, spicy salsa stays fresher longer, while mild salsa tends to lose its flavor more quickly. Capsicum, the molecule responsible for pepper heat, is known to have antimicrobial properties that can increase your salsa's shelf life.
This might be a good thing with Roy's recipe, given his technique skirts the margins of standard food-safety guidelines, and would probably not be endorsed by your local extension agent. Roy uses a technique called "hot packing," whereby you pour hot food into hot, sterile jars, but don't further boil the jars once they're packed. I've made hundreds of quarts of Roy-style hot-packed salsa over the years without a problem, but I'm not suggesting you do what Roy and I do. I'm simply informing you of his methods as he showed me. You should know the basics of canning before attempting to follow this or any canning recipe.
Preparing salsa for canning is a different and less forgiving process than making salsa from scratch in summertime. Anyone can chop some fresh tomato, onion, cilantro and jalapeno, with little regard for proportion, and sprinkle with salt, pepper and lime juice, and it will taste good. Canning salsa requires exact proportions of precisely measured units. Roy's unit of choice is the food processor load.
He downplays the rigorous nature of his kitchen science, claiming, "I just throw some she-it in jars." But the truth is that when the ingredients are assembled and it's time to make salsa, Roy leaves little to chance.
The ratio of tomato to pepper should be about one to one by uncut volume, which is about three to one by weight. For 40 pounds of tomatoes, you'll want 13-15 pounds of peppers, 10 large onions, three pounds of carrots and six heads of garlic.
High-acid canning tomatoes are ideal, and your choice of peppers can include as many shapes, colors, sizes and flavors as you like.
Roy uses jalapeños, bells, Anaheims, wax, and any other fresh pepper he can get his hands on, plus crushed dried chile flakes, hand-crumbled dried whole chiles, a few habañeros, and for good measure a can of Mexican-style pickled carrots and peppers, all run through the processor. Those with little heat tolerance can assemble a diverse collection of mild, sweet and flavorful varieties. Those who like it hot should remember to remove your gloves before using the rest room.
Mince your ingredients in the food processor, leaving no chunks larger than a pea, and add the chopped loads to a large pot according to the following proportions: "Five loads of tomatoes, five loads of peppers, two loads of onions, one load of carrots, half a load of garlic."
When the pot is close to full, mix the contents, turn on the heat, and bring it to a boil, stirring and scraping frequently to prevent scalding. While heating, add salt and pepper to taste. Be prepared to cough from the vaporizing capsicum.
As soon as the mix hits a rolling boil, turn off the heat, ladle the salsa into hot sterilized jars, and screw on sterilized lids. The hot-packed jars will seal as they cool.
Late summer is the ideal time to make salsa, because the supply of local salsa ingredients is at its high point. This translates into market pressure that's valuable to understand.
I'm not at all telling you to haggle with the growers at the farmers market. They work hard, with considerable risk and little margin, and they probably don't want to help you practice the negotiating skills you picked up on the streets of Cancun. At farmers markets on this side of the border, attempts to bargain generally come off as obnoxious.
That said, during harvest season there are deals to be made that can mutually benefit both parties, especially as the market is winding down for the day. When it becomes clear that a farmer is going to have tomatoes left over, let him or her know you're looking to go big. You might want to start the bidding by asking, "How much for that whole box?"
While some growers will take home leftovers to process themselves, others are so busy and overworked, with more tomatoes ripening on the vines, that their leftovers go to the compost pile. If you can identify these farmers, you should be able to arrive at terms beneficial to everyone. Such terms might involve the delivery, at a future date, of a jar of homemade salsa.
Roy likes to make plenty of extra jars to give away, once he's confident the recipient can handle his heat. He may also suggest diluting the salsa, either with avocado to make guacamole or with extra tomatoes. I myself like to stir in a little mayo, arriving at a pinkish mixture I call "super salsa." These are important tricks to know, in case one of us gifts you a jar.