Crushing oak galls is great therapy!

 I just put the oak galls in a plastic bag & hit them with a hammer until all of the galls were broken into pieces.

Although there was a bit of powder after I crushed these galls, you can see I didn't totally pulverize them.

Ideally, you'd reduce all the oak galls to powder. The more surface area you create, the faster the gallo-tannic acid will leach from them.

Since I wasn't home much this weekend, I decided to try this recipe where you allow the oak galls to 'ferment' in water for 10 days or so. That way, I don't have to let them simmer/boil for several hours while I watch & stir.

Here are the quantities I'm using for this batch:

Oak galls - 4 parts by weight (In this case 4 ounces)

Iron Sulfate - 2 parts (2 ounces)

Gum Arabic - 1 part (1 ounce)

Water - 32 parts (32 ounces, or about 4 cups)

None of these measurements are exact. I'm using a 100g package of oak galls which is 3.527 ounces. I'll probably use a tablespoon to measure the iron sulfate & gum arabic.

4 ounces of smashed oak galls added to about 4 Cups of water in an old pickle jar. 

I've added the oak galls to tap water & loosely covered it with a lid to keep out contamination. After letting the mixture sit for 10 days, I'll filter out the chunks, add iron sulfate & gum arabic and see what happens. I'll probably crunch some more galls in the meantime & try a recipe where the galls are boiled before adding the other ingredients. Maybe I'll even try a batch with wine instead of water.

I'll post another photo tomorrow to compare if the water is getting any darker.