I think washing grains is a matter of choice. Dom's site provides instructions for washing grains, but states that it's not necessary unless production decreases or it takes longer to get initial separation of curd and whey.

My grains are producers. I'm getting to the point where I need to add more milk, separate my grains, or add some of the grains to a smoothie for consumption. The grains are multiplying, and I just received them and started using them on Wednesday. I'll avoid washing them for the time being.

Tried an 8 ounce glass of kefir today and stirred in a quarter teaspoon of vanilla extract. Nice flavor and very rich where I wouldn't need a sweetener. I'm now using local whole milk that's grass fed with no additives of any kind. I can tell I may have to add more milk and make larger batches, as the separation of curd and whey starts to occur from 21 to 23 hours, where in the first few days, I could go over 24 hours before I'd see any separation.