There are lots of variables going on with this seemingly simple sauce, so don't freak out if it doesn't taste exactly like Tabasco. It'll still be great. Your chiles will affect the flavor, as will where they were grown. So will your salt -- don't use iodized salt, it will muddy the flavor -- and your vinegar. Tabasco's private stock is made with white wine vinegar, and it is noticeably better tasting than the stuff you buy in the store. Use a good vinegar. And you really need the toasted oak cubes to get the full Tabasco effect. They store their mash in oak barrels, and unless you are making that much sauce, the oak cubes are the way to go. You can buy them at any winemaking shop or online. Try to let the mash ferment as long as you can. Every month you let it go makes it better. Finally, this recipe can be scaled up or down. Just remember, the key ratio is 2 percent salt by weight of the chopped-up chiles.
Roughly chop the chiles and compost the stems. Blitz the chiles in a food processor or blender with the salt and water until you get a rough paste or slurry, depending on how much moisture there is in the peppers themselves. I keep the seeds in the chiles, but if you want a milder sauce, remove them.
Put the mash into quart mason jars and cap them loosely. "Burp" the caps at least once a day to let out escaping gases and let air in. The chiles will ferment like this for at least a week, and sometimes up to 3 weeks. When the chiles settle down, add the oak cubes, distributing them evenly throughout the jars. Tighten the lids and store the jars in a cool, dark place. I kept mine in my salami fridge, which is 55°F. A basement is fine, as would a fridge. Tabasco keeps their mash barrels at ambient temperatures, which in Louisiana can top 100°F. I am working on a batch fermented this way now, and I see no reason it won't work. Don't let the mash freeze, however.
Keep the mash like this no less than 3 months, and up to 2 years. When you are ready to finish the sauce, mix the mash with the vinegar.
You now have two choices: You can do what Tabasco does and return the mix to the jars, shake them every day for a month and then strain out the pulp and seeds. Or, do what I do and keep all that pulp, which will give the sauce body and thickness. If you choose my method, you will need to really blend the sauce and stabilize it -- otherwise the sauce will eventually separate and will need to be shaken up before each use. To do so, dissolve the xanthan gum in 2 tablespoons of water and add it to the blender. Blend for a solid minute. Let the sauce rest for 1 hour before bottling so any trapped air in sauce (from the blending process) can escape. Bottle and store. The sauce will keep for a year or more.