Step one

Collecting the ingredient

• Oak knopper galls - I collect my oak galls from the ground when they have fallen from the oak tree. You can collect and use oak galls freshly, but this will usually give a lighter natural dye.
• I have been collecting mine for a few years and I leave them outside in an old metal bucket with a loose lid, where they are exposed to the air, water and the metal of the bucket. This means the dye can be created on it’s own without cooking, as the combined elements create a dark brown colour of the water to make a mordanted dye or ink of the oak galls. (See the last step for more information about Mordanting)

Step two

Preparation and recording

• Once you have collected the oak galls, weigh out the quantity you desire and make a note of this in your journal or lab book. This can be useful if you want to repeat the recipe many times and record your results/variances.

Step three

Cooking

• Add the oak knopper galls into the saucepan
• Add the 500 ml of tap water. I have also used rain water. The water  can be cold or preheated; either may change the result of the final mixture.
• Cover with a lid and cook the ingredients in the saucepan on a low heat for 20-30 minutes. It is a good idea to keep an eye on the saucepan so it doesn't bubble over
• Depending on the strength of the dye, you can continue to top up the water and cook.

Step four

Pouring and storing

• Once you’ve got your desired colour, you can also strain or sieve the mixture into a measuring jug. Let it cool and make a note of the natural dye volume.
• Another option is to strain or sieve the mixture into a jar with the oak galls. Let the dye and the oak galls cool, then place on the lid tightly and store this to use another day. You can store it in the fridge or at room temperature depending on when you want to use it.
• You can use this natural in replacement or in conjunction with the water ingredient in many bioplastic and biomaterial recipes.
• You can also use the dye in a concentrated form as an ink to write or paint with.

Step five

Ingredient info:

• Oak galls actually start as small green acorns into which gall wasps lay their eggs. The wasp larvae grow inside the galls and the chemicals they secrete change the normal oak tree tissues from the smooth acorn shape into the gnarly bumpy forms of the oak knopper gall. When they crawl out they leave a perfectly formed circular tunnel which also helps the oak galls to dry and become rock hard.

Step six

About Mordanting

• If you are going to use this to naturally dye textiles, make sure the fibre of the yarn or textile cloth is a natural fibre i.e. from a plant or an animal.
• A mordant is an ingredient/ substance which is usually an inorganic oxide. When it combines with a natural dye it helps to fix that material with the colour and is especially used in natural textile dyeing. 
• The word ‘mordant’ comes from the Latin mordere which means ‘to bite’ (in spanish mordar or french mordre), so imagine the mordant helping the natural dye to ‘bite’ onto naturally dyed textile.
• If you are going to use this to naturally dye textiles, make sure the fibre of the yarn or textile cloth is a natural fibre i.e. from a plant or an animal.