Gather your ingredients together.
Wearing gloves slice the jalapeños.
Discard the seeds if you prefer.
Fill a half pint jar (with an air-lock lid) with jalapeño slices.
Press down on the pepper slices to pack them into the jar.
Separately, in a glass container mix together the water and salt to make a brine.
Pour the brine over the jalapeños leaving 1 inch from the top for expansion space.
Place the lid on tightly.
Allow to ferment at room temperature for 1-3 days.
It will last for months in the fridge.
A great topping for pizzas!