All recipes for sofer's ink centre around three basic ingredients:
1. Oak Galls -Afeitzim
Here is the torymus sp. perched on a blade of grass, which gives the scale of the insect.
These ferrous sulfate crystals are approximately a centimetre across, for our purposes we will use copperas reduced to about the consistency of table salt.
For a fuller, and quite interesting description of how ferrous sulphate is produced I recommend the following CR Scientific Experiment page www.crscientific.com/ferroussulfate.html
Here's the basic formula for ink. I've reduced it somewhat as the original recipe I have yields some ten gallons of ink. I write a lot, but that's more ink than I could use in two lifetimes. This will produce about 2 quarts of fine, durable ink.
3 oz oak galls
1 oz logwood shavings
2.2 oz gum arabic
1.9 oz copperas
The trick to making really, really good iron gall ink is long, slow cooking of the galls and logwood. Some recipes I've seen call for just tossing all four ingredients together in a jar of water and allowing it to 'macerate' for a few weeks. This is great if you want to write with a disappointingly grey ink. However, if you're like me and want an rich, deep black ink, straight from the bottle then we need to prepare the ingredients a bit more.
Stage One: Assemble, weigh and prepare the ingredients for cooking.
**Be sure to use containers specifically designated for non-food use. There's a good chance that these ingredients will leave a residue that would not be so good to ingest. So just like our meat and dairy dishes, we keep our ink pans separate.
At this point the logwood and the oak galls have been reduced finely and soaked in hot water over night. We are now ready to begin the cooking process. The cooking process involves three separate boilings. In the first, take the galls and the logwood and put them into a 4 quart stainless steel pan and add four cups of water, distilled if possible. Chlorine, flouride, salts and minerals in tap water do funny things to ink over time.
First Boiling: Over a medium fire, boil the galls and logwood for one hour. Replenish any liquid lost to evaporation. Strain the liquor and set it aside.
Second Boiling: Using the same galls and logwood add 2 1/2 cups of water and boil for half an hour. Strain the liquor and add it to the first.
Third Boiling: This time add only 1 1/2 cups of water to the galls and logwood. Boil for half an hour, and add to the rest. Allow the whole lot to cool and steep over night.
The next day, using a bit of flannel, filter the liquor into a separate container. Then squeeze the galls to extract whatever potency they may have left.
The liquor as you can see has turned a very deep brown. If it comes in contact with your skin it will leave it looking quite orange and shiny. Add water if necessary to make up the full two quarts. Using a pitcher marked for quarts is useful at this stage.
The next day, I measured out the 1.9 ounces of copperas and crushed the 2.2. ounces of gum arabic to powder then dissolved it in about 1/2 cup of hot water.
Return the gall liquor to the fire and heat it until it is quite hot. Then add the copperas and stir vigorously. The dark brown of the galls will turn deep black in seconds as the chemical reaction between the gallo-tannic acid and the ferrous sulphate takes place. Then pour in the tincture of gum arabic and stir.