Cut the end and the tip off of the serrano peppers and place them in a clean sauce bottle. Tamp down the peppers slightly and fill up the bottle about 1/2 with peppers.

Mix the vinegars and bring them to a boil.

Slowly pour the vinegar into the bottle using a funnel. Fill the bottle up to an inch of the top and seal the top with a cap or cork.

Let the bottle sit at room temperature for a minimum of one week before using, but three weeks is recommended for optimal heat.