Shops I found while sourcing fermentation ingredients across Mexico City

Saturday morning, while organizing the kitchen shelves, I discovered that one of my ollas de barro was cracked. A fine fracture had formed on the inside, and salt water was slowly seeping through. I'd been using that clay pot for over half a year to ferment chiles, and I briefly wondered where I'd need to go to find a replacement. Then it occurred to me that it might be worth putting together a guide to the routes for sourcing fermentation ingredients and tools in this city. If you work in a professional kitchen while also keeping fermentation projects going at home, a lot of this will resonate.

La Merced Market, the Pottery Alley

La Merced market is so large and maze-like that it's easy to lose your bearings on a first visit. The section I look for is on the east side of the market, a narrow passage where they sell pottery and kitchen tools. This is where I buy ollas de barro for fermentation. The key is finding traditional, uncoated clay pots, and since glaze treatments vary from shop to shop, you absolutely have to touch the inside surface yourself. I avoid glazed ones because the glaze eliminates the interaction between the microorganisms and the clay during fermentation.

The shop I go to most often is about halfway down the passage, with no sign, just stacks of ollas and cazuelas. The owner is from Oaxaca, and if you ask where the pottery was fired, he'll give you a pretty detailed answer. A single pot usually runs between 80 and 200 pesos, depending on size and thickness. If you tell him you're using it for fermentation, he'll sometimes pick out one with thicker walls for you.

Dried Chile Vendors at Jamaica Market

Mercado de Jamaica is famous as a flower market, but if you go deeper inside, you'll find a section specializing in dried chiles and spices. This is where I buy chile morita, chile pasilla, and chile ancho. When choosing chiles for fermented salsa or a mole base, it's important that the drying is uniform, and the vendors at this market tend to have fairly consistent quality from lot to lot.

One tip: when buying chiles in bulk, ask for them "por kilo" and you'll pay much less than buying them individually. For pasilla, it's roughly 120 to 180 pesos per kilo, though it fluctuates depending on the season. I usually buy 2 kilos at a time, portion them out at home, put some straight into fermentation, and seal the rest for storage.

Coyoacán: Fermentation Cultures and Glass Jars

Over in Coyoacán, there are a few small shops that carry health foods and natural fermentation supplies. This neighborhood is where I first got my kefir grains and kombucha SCOBY. These kinds of cultures are hard to find at big supermarkets, and when I've ordered them online, temperature wasn't controlled during shipping, so they often arrived in poor condition. At a shop tucked into a side street just off Coyoacán's main square, they sell portions of SCOBY they've grown themselves. You can check the condition with your own eyes before buying, which gives me a lot more confidence.

I also source glass fermentation vessels in this area: wide-mouth glass jars, airlock lids, glass discs for weights, and so on. Prices range from 150 to 400 pesos depending on the size of the container. I use the 3-liter size the most. My kitchen at home isn't exactly spacious, so anything bigger is awkward to fit on the shelves.

Sonora Market, an Unexpected Find

Mercado de Sonora is known for its herbs and traditional medicinal ingredients. It's not a market I'd normally go to specifically for fermentation supplies, but one time a colleague was looking for aguamiel for pulque fermentation, so I tagged along and ended up making some unexpected discoveries. Among the dried herbs, there was a stall selling leaves that can add aroma to fermentation (things like epazote and hierba santa) in excellent condition. The prices were lower than at other markets, too. That said, this market has a complicated layout and gets very crowded, so if you wander around without a plan, you'll just burn through your time. Better to decide what you're buying before you go.

What I keep coming away with after visiting all these shops is that fermentation, in the end, starts with the condition of your ingredients. It's the same principle when cooking on the line, but fermentation takes longer, so differences in initial ingredient quality show up even more dramatically in the final product. Walking through the markets yourself, touching things, smelling them, talking with the vendors as you choose, it's time-consuming, but that effort comes back to you in the results when you open the jar days later. Next time, I'm planning to explore a small organic shop over in the Tlalpan area.