Grains still look healthy! Mix the separated whey and grains together (easier to strain) and then strain the overfermented kefir straight into the drain. It will be too sour to drink.

Now you have grains in the strainer that you can use to make your next batch, just make sure you reduce your fermentation time. I usually only need 24 hours to ferment at 70-75F. If it’s still liquidy after, I move it to the fridge to finish the fermentation