Natural dyeing – Oak Galls

Green oak galls

Green oak galls

I’ve read about oak galls and their place in dyeing and ink-making a little, and didn’t think too much of them – I don’t really think of oak trees in Calgary (compared to trips to Louisiana!) but while out for a walk (playing PokemonGo!) I noticed that one of the parks near me had cute little (young) oak trees. A closer look… and there were the weird clustered balls.

According to the city parks website, I’m pretty sure these are Bur Oaks (Quercus macrocarpa), sometimes called mossycup oak and mossycup white oak. If any of my more horticulturally-inclined friends know otherwise, please let me know!

Now… they’re a LOT smaller than I expected oak galls (also known as oak apples or oak marble galls) to be, but I had my fingers crossed that they would work for dyeing/mordanting. I also don’t know if the galls from Bur Oaks will be as high in tannins as from other varieties of oak… but hopefully still enough to get good results.

More photos of what I expected oak galls to look like on Wayne Armstrong’s website.

Since it was late summer when I first found them, I was seeing a LOT of green oak galls – without any holes in the galls to indicate that the wasp had vacated. However I did find some that were probably from a previous season or earlier in that season – which DID have the hole, so those were the ones I collected. I’m not sure if “old” galls are better or worse than ones recently vacated.  (So many questions! If you know any of the answers, please reply in the comments below!) 

Brown oak galls with the hole in them

Brown oak galls with the hole in them

A few weeks later I returned to the park and collected even more – (almost) all again with the hole in it (as above). Apparently I’m not the only person on the hunt for oak trees in Calgary, this reddit thread has a few answers (and some of them even have potential!) In the meantime though, I’m carrying a small ziplock bag in my purse…  Not only do I want to find the tree- but one with branches low enough to collect the galls from – super tall established trees trimmed to provide a nice shade canopy won’t help much at all!

I also visited a second park with young oaks, but it had almost no galls – I suspect this location sprays for pests, and thus no wasps were there to create the galls.

Oak galls to hopefully use for natural dyeing

Oak galls to hopefully use for natural dyeing

Even though we’d already had snow, some of the galls were still ‘soft’ and didn’t have the tell-tale hole, so I ziplock sealed the baggie, and then when I got home tossed the baggie in my freezer… to kill off any wasps still inside the gall.

Oak galls as a mordant

I visited Griffin Dyeworks which has a pretty great run down about different products they carry – but also alternatives which were way more interesting to me. For Tannic Acid, they describe it can be used as a pre-dye additive or as a final rinse; results will be different for both. They indicated it will add brilliancy and fastness to some dye colours, and “enhances reds with tin”.

“Mordant (with tannic acid) before using a metallic mordant (copper, iron, tin) to create a good bond with cellulose fibers. Darkens fiber with age. “Antiques” bright colors. Useful as a rinse to neutralize fibers dyed in alkaline dyebaths, such as indigo vats: use 1 tsp tannin dissolved in the rinse water.” 

Best On: Especially good on silk, cellulose fibers; not good on wool
Dye Recipe: To mordant with powdered tannin: add 1 tbsp tannin to 1 lb fiber, simmer well-soaked cellulose fiber in liquid 15-20 minutes, continue with dye recipe. To mordant with plant tannin: soak tannin 24 hours, boil without fiber 1 hr, strain to remove plant pieces, add fiber, simmer 1-2 hours or as directed in dye recipe. Add 1/2 c vinegar to last rinse. For darker dye, use more tannin. Renew mordant pot with 10-15% salt, 2% soda ash, 1% Glauber’s salt to weight of tannin. For blue-black color, mix tannin with iron.
Safety: Very dangerous to inhale powder! Use mask and safety goggles; do not wear contact lenses when working with tannin; if powder gets in eyes, wash eyes constantly while someone calls for medical help. California Proposition 65 Warning.
Disposal: Pour on any tree or neutralize with baking soda, pour down toilet or sink
Galls, Oak galls, Gall-nuts: Abnormal growths caused by insects; 60-78% gallic acid. Boil 1-2 hrs: 1/4 lb galls to 1 lb cotton. Turkish galls: 50-60% tannin; Chinese galls: 70% tannin

So really.. it’s only that LAST paragraph that I’m really interested in – the one that talks about alternatives to their powdered tannin product, and instead talks about the oak galls as a source of tannins instead.

In Wild Colour, Jenny Dean writes about oak galls as a mordant as well. While she notes chemical mordants like aluminum, copper, and iron, she also suggests natural mordants like oak galls and staghorn sumac leaves. These are rich in tannin she notes, which helps colour adhere and increases light and wash-fastness, specifically on vegetable fibres.

In addition to acting as a mordant on vegetable fibres, she also notes that oak galls can be used to further improve the absorption of alum and copper mordants before dyeing.

Jenny suggests 4oz (100g) of oak galls for 1lb (500g) of fibre. She also suggests substituting staghorn sumac leaves for the oak galls if desired to the same quantities. She writes that while some tannin solutions add colour of their own, the tannins from oak galls and staghorn sumac leaves imparts only a pale beige or light tan colour to the fibre, thus providing a ‘truer’ dye colour.
Jenny notes that bark and leaves of trees also contain tannins, such as oak, alder, or willow – but these impart more colour, thus impacting the final dye colour.
Her recipe for using oak galls as a pre-mordant is:
  1. Wet the fibre by soaking in water between one hour up to overnight.
  2. Simmer the oak galls (or sumac leaves) in about 4 gallons (18 liters) of water for one hour
  3. Leave the solution to cool, then strain off the tannin liquid.
  4. Soak the wet fibre in the tannin solution for 8-24 hours, rinsing well before proceeding with dye or additional pre-mordants.

The oak galls can be dried thoroughly, and then reused for another batch of solution. She doesn’t indicate if the second round will be less potent and need a perhaps higher quantity of galls per liquid/fibre.

After using the tannin solution, Jenny writes that it can be cooled and stored in a plastic container. When the solution no longer produces a beige or light tan colour on fibres, it is exhausted and should be discarded. She notes that mould may form on the top of the solution, but this can be removed and does not impact the viability of the solution.
In Wild Colour, Jenny writes that tannin solution mordants are good for lighter, brighter dye colours when the solution is weak, and darker dye colours when the tannin solution is strong. I think she means the intensity of the dyes (increasing the quantity of oak galls in proportion to fibre) rather than the colour of the solution.

Oak galls as a dye

In Wild Colour, Jenny Dean also explores the use of oak as a dyestuff, showing browns from the bark, yellows and greens from the leaves and yellows and browns from the acorns (depending on mordant and modifiers). Of course what I’m most interested in a the range of colours from the galls – from pale beige when used without a modifier, to beautiful greys when used either with a modifier and mordant, or modifier only.
Bur Oak Acorns - all windfall collected for possible natural dyeing.

Bur Oak Acorns – all windfall collected for possible dyeing.

Jenny notes that no part of the plant requires a mordant, and to use equal parts of dyestuff and fibre for bark, leaves, acorns, or galls. Small amounts of iron modifiers gives “attractive greys” she notes. Harvesting time for the leaves also impacts colour, with fresh leaves collected from windfall producing brighter colours, and fallen autumn leaves (either used fresh or dried) producing brown shades.  I was reading this in mid November, and all the leaves had long fallen to the snow, but this might be something to try next year…

For the oak galls, Jenny recommends collecting them before they turn brown and hard, as this is when the tannin content is the highest. Of course, I collected mine long before reading this, and when I did read it it was already mid-November, far too late to collect fresher galls, still I’ll know for next time!
She recommends crushing the galls and soaking them in water until they are soft. From there, simmer the galls for about one hour, and then strain off the solution. The galls can then have more water added and simmered again to extract more tannin from the galls. To use the galls as dye, she recommends either add iron to the dyebath, or use an iron modifier after dyeing. She suggests that to darken the colour, the fibres can sit in either the dyebath or iron solution overnight. I wouldn’t want to soak my wool in iron, but I suspect that the oak gall liquor would be less harmful.
Jenny Dean mentions “in medieval times, this method of adding iron to the oak gall dye liquid or using an iron modifier after dyeing was a common way of producing a black colour on wool fibers.  However, some dyers, keen to save both time and expense, added iron fillings to oak gall dye liquids, instead of using ferrous sulfate or iron liquor, and this had a harmful effect on the wool, making it feel harsh to the touch and weakening the fibers.”
Since oak galls can be used as a mordant or a dye… and iron can be used as a mordant or a dye – I’m unsure how to accurately describe a oak-iron mordant/dye combo…

Preparing my galls

I started of with 144 grams of galls, but decided not to use them all for my first experiment. I had originally hoped to partner up with a friend, but she was feeling poorly, so I thought I’d reserve some for when she might be feeling better. November 24 I poured out a bunch (in sections) onto folded paper towel on my cutting board and beat them up so they broke into pieces (and a little bit of powder too… note to self: wear a mask next time). I likely could have used a mortar and pestle but mine is packed away somewhere… and this worked fine.
When I measured, I had 38 grams of galls remaining (uncrushed) indicating I had 106 grams of galls crushed up and ready to use. I put them in a mason jar filled with snow, let the snow melt, and let the galls soak. (I added more snow when needed until the jar was full of liquid.)
Like in my apple tree dye experiments, I opted to use snow to avoid the extra (hard) minerals in our water, and any chemicals added by water treatment. Plus it had just snowed overnight, so there was lots of fresh snow available! It was interesting to see how quickly the liquor forming was already starting to change the fresh white snow, turning it a soft brown, within an hour or two of adding the snow and crushed galls to the jar.

Mordanting with galls

The soaked galls looked pretty weird -they leached a LOT of their colour into the snow-water surrounding them, which I think was generally the point.  They looked rather mushy and weird – kind of like a gross breakfast cereal..

On December 5, eleven days after soaking the galls, I poured the mixture of galls and snow-water into my dye pot, and added enough more melted snow water to immerse my yarn and fabric for mordanting. I turned the heat on slowly, warming the mixture for about 30 minutes (with my stove at 4/10). Then I increased the temperature to just under a simmer (6/10) and kept it there for about an hour. Then I let the mix completely cool on the stovetop.

The resulting liquor was the colour of… beef broth – but when I dipped a white paper towel into the mix, and dried it off a bit, the towel was only a light brownish-yellow.  I was quite happy with this, since my hope was for a mordant that didn’t impact the colour of the dye substantially.
The next day I strained the liquor through a piece of linen (I first used a coffee filter but it took way too long) and re-heated, adding my fibre.
For the first batch I used four skeins of handspun wool yarn. Two skeins are the two-ply Romney (UK) natural white (so a soft ivory) and two skeins are single-ply. I also dyed/mordanted a piece of silk noil, and a piece of white linen.

The results

Oak gall dyed wool yarn, silk and linen fabric, show with an undyed sample of wool for colour comparison.

Oak gall dyed wool yarn, silk and linen fabric, show with an undyed sample of wool for colour comparison.

I anticipated that the dye/mordant would only lightly colour the fibre… I was wrong.
The wool took on quite a bit of colour, as did the linen. The silk took on a fair amount of colour as well.  The colour is sort of a brown with a bit of yellow behind it – not a particularly desirable colour in my books… but we’ll see what happens when I add a coloured dye over top!
Oak gall dyed wool yarn, silk and linen fabric, show with an undyed sample of wool for colour comparison.

Oak gall dyed wool yarn, silk and linen fabric, show with an undyed sample of wool for colour comparison.


Want to see the next steps?

Green oak galls

Green oak galls

If you want to see more of my work-in-progress photos, come follow me on Instagram! If you want to see more finished projects, please either subscribe to my blog, or follow me on my Dawn’s Dress Diary Facebook page, where each of my blog posts gets published so you can see when new posts come out.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.