Coaxing Color From Oak Galls
Oak galls are very high in tannins, so they’re both a mordant and a natural dye. It all depends on how you process them. If you’re anything like me you’ve been collecting and admiring them over the past weeks. I keep mine stored in giant glass jars or plastic tubs depending on how many I have on hand. It’s good to label the containers with the date. Use the older galls first. As long as you keep them dry, in a cool dark place, they last forever. Before you store them make sure they are completely dried out and all the wasps have hatched. It’s also important to inspect them for mold. If I find some with a little mold I just clean it off with a damp cloth and put it in the sun to dry. Then I put them in a separate pile. I’ll check on them again in a week or so or just use them right away. All my Instructions are for plant/cellulose fibers. I do dye silk from time to time, but I have little experience dyeing protein fibers like wool. If you’re using protein fibers that may felt, it’s important to add them to cool water, then heat.
Pounding, Cracking & Crushing
When I’m ready to use the oak galls I smash them with a hammer or smooth rock. I have a giant tree stump I smash them on with a baby sledgehammer. it makes for quick work. If you don’t have a tree stump, just make sure you break them up on a stable surface. When breaking up the oak galls, the smaller the pieces the better. you’ll want to at least crack them in half or quarters depending on how big they are. I usually break them up and then put them into an old coffee grinder that I have set aside for grinding natural dyestuffs, such as cochineal, manzanita bark, madrone bark, oak galls, and osage orange sawdust. They don’t need to be completely pulverized to speed up the extraction process.
You have 2 options for extraction. If you want instant gratification you’ll want to heat up water. I do the majority of my dye work outside. I have an inexpensive single electric burner that’s good for regular-sized pots. Exposed coil burners have a weight capacity, so keep that in mind. I use a cast iron propane camping burner for anything more than 2 gallons. If you’re working indoors make sure it’s well ventilated. open the window and turn on the exhaust fan. Oak galls aren’t stinky just earthy and all-natural dye work should be done in a well-ventilated space.
Mordanting
You’ll want to use 20-30% w.o.f. If you have 100g of fabric you’ll need 20-30g of oak galls.
Cold water/low-energy
Cold water extraction works great for mordanting, it just takes a little extra time. Lower temperatures keep the galls from oxidizing, which can lead to darker colors. Usually, we want the most neutral color for a mordant. Just soak the crushed galls in a bucket or plastic bin for several days. Give them a stir once a day and check the color. When it’s a golden brown it’s ready to use. This usually takes 2-4 days depending on the temperature. the warmer it is the better. Always keep the bucket covered with a lid. You don’t want anything crawling in there and drowning. I found a woodrat once and I was so sad. Woodrats are native to my area and super cute.
Hot water extraction
I start by using hot tap water, then heat it to around 140F. Turn off the heat and let it steep for 2-4 hours with the lid on. Try not to heat above 140F. Higher temperatures cause oxidation and darker colors. It’s important to have a digital instant-read thermometer. This is the one I have Javelin Digital Instant Read Meat Thermometer it was $26 and it works great. Plus it has a magnet so I keep it on my fridge so I don’t lose it. Remember this is only for natural dye use. Any and all equipment used for natural dyeing must be separate from cooking equipment.
Once things have steeped for the required amount of time, depending on which method you used, strain out the oak galls, and add the pre dampened fabric. There should be enough liquid in the pot for the fabric to move freely. You can add more water if needed. You’ll want to heat the solution to 120-140F. Leave the pot covered and turn off the heat. You’ll want to stir it once an hour. The fabric is ready to use after 2-4 hours. Gently rinse and it’s ready. If you want to save it for later, hang it in the shade to dry.
You can reuse this water for more mordanting. You’ll just need to add more oak galls and repeat the process. If you’re not going to reuse it, water a tree or some plants with it.
Natural Dyeing
You’ll want to use 50-80% w.o.f. depending on the desired shade of color. Always pre-dampen your fabric by soaking in water for 20-60 minutes, wring out excess water before adding to the pot.
If I’m extracting for color I start with hot tap water. This cuts down on the heating time. You’ll want to heat the water to 180F - 200F. You don’t need to boil the solutions. I usually bring it up to the desired temperature, turn off the heat, and let it steep for 2-4 hours. For even colored fabric you’ll want to strain out the oak galls. Add the fabric and give it a stir. There should be enough liquid in the pot for the fabric to move freely. If there isn’t add more water and bring it to temperature. You don’t need to constantly stir, Just check on it every 15-20 minutes and give it a good stirring. You can get rich champagnes and soft golden brown tones depending on the strength of tannins and the length of time in the pot. You’ll want to leave it in for at least 30 minutes. This gives the tannins time to bond to the fabric. it will take 1-2 hours for darker colors. Once you’ve got the desired color, remove fabric from the liquid giving it a good squeeze, and hang to dry out of direct sunlight. I wait for 24-48hrs before I wash my fabric. Always use a Ph neutral soap, cold water, and the gentle/hand wash cycle to wash anything you naturally dyed. you can dry it in the dryer or hang it to dry out of direct sunlight.
If you’re wanting to create gray tones you can add small amounts of ferrous sulfate 2-3% directly to the pot or make a separate solution for an iron afterbath. You can also make homemade iron water. So start collecting those rusty objects.
If you don’t have oak galls in your area you can purchase whole and ground oak galls from Botanical Colors. They also carry Gallo Tannin extract which is the concentrated form of oak galls.