Alternate layers of peppers and garlic slices in a clean mason jar. You'll want to lay them in the jar as flat as possible to get the most amount of peppers in the jar. You want to leave an inch of space between the top of the peppers and the top of the jar.
In a bowl, mix whey, water, and salt.
Pour the whey mixture over the peppers, leave 1 inch of space for expansion between the top of the liquid and the top of the jar. Make sure that all of the peppers are covered by the whe. You may need to add a bit of extra water.
Put on the mason jar's lid and allow to sit at room temperature for 2-3 days and then move the jar to cold storage. We keep ours in the fridge.