Remove the stems from the jalapeños and slice each in half lengthwise. Use a spoon to remove the seeds for less heat if desired.
Add the jalapeños to a blender along with the garlic, salt, 2 tablespoons vinegar and water.
Blend on high until totally smooth. This may take several minutes depending on your blender. Taste and add more salt and/or vinegar if desired.
Transfer hot sauce to a jar and refrigerate for up to 3 months.
If desired, you can ferment the hot sauce by leaving the jar out at room temperature, covered, for about a day. This will give it a deeper, more interesting flavor. Refrigerate after fermenting.
You can also cook the hot sauce for a milder, more mellow flavor. Pour the mixture into a sauce pan and cook, stirring constantly, over medium heat until the color changes to a deeper, duller green; about 2 minutes. Remove from heat and allow to cool before transferring to a jar.
All three methods produce excellent results. Experiment with them until you find what flavor works best for you!
Notes
Wear gloves when handling hot chilies or the capsaicin can stay on your hands for hours and be quite painful.
Chili peppers can vary widely in their heat. If your jalapeños are especially hot, remove the seeds and ribs with a spoon before blending.
Be sure to thoroughly blend the hot sauce so it is very smooth texture. If there are still some chunks or if you prefer a thinner hot sauce you can pass it through a fine mesh sieve or strainer.