Thursday, March 17, 2016

Sap Green 2 from Buckthorn berries

This is the continuation of my research on trying the medieval paint recipes for Sap Green from Buckthorn.

Once I figured out what Buckthorn berry bushes looked like I began to see them everywhere.  Consequence?  More experiments!

I visited my good friend Shana Clark in New Hampshire to raid her local Buckthorn bushes in early September.  They were growing in a more open area in more sun than the ones in the first experiment.  The branches were full of berries, mostly ripe and dark and with a few green.  The next day I sorted them into 53g of green and 341g of ripe berries.

I had already experimented with the Iris Green paint recipe from De Arte Illuminandi with pretty results so I was excited to put the recommendations for Buckthorn to use.

De Arte Illuminandi, pg 7
And it's note: 

De Arte Illuminandi (Thompson and Hamilton 43)

Then the recipe:
De Arte Illuminandi (Thompson and Hamilton 7)
Adrienne's Experiment steps:
Collect materials
Suit up with nitrile gloves, goggles over glasses and dust mask!

I took 100.00g of ripe buckthorn berries and crushed them with a plastic fork.

In a glazed porcelain (corningware) sauce pan I mixed 11.60g of lye (K2CO3) with about 100g distilled water.  Adding 5.05g of alum (aluminum sulfate) resulted in immediate bubbling.  The reactions at this point have raised the temperature a little to 80F.  Warming the mixture on a simmer burner on low, I hoped to dissolve more of the alum.  After about ten minutes the bubbling had mostly stopped, the temperature had risen to 120F and the solution had a pH of 6 with a milky appearance.  After heating it up to encourage the alum to dissolve and losing a little in the sink when I poured it into the jar with crushed berries, the total weight of the solution had decreased to 87.07g.  There was also a little residue left in the pan.

I mixed the solution into the berries with the same plastic fork I had used to crush them.  The next day I found the solution bubbling out of my pint jar!  I got rid of the beautifully green paper towel beneath my jar and put it in a glass bowl.  As the recipe directs I "let them stand so, out of the way, for three days".  After they had rested I used a clean square of linen to strain the juice into another jar.

The next week I painted it out!  What a beautiful green!


  1. Sounds like the alum you used worked, but actually, the right alum to use is "Rock Alum." That is such as alunite, aluminum potassium sulfate.

  2. Thanks so much, Randy! I never noted why I thought the alum I bought was the correct one. Curse common names. I should have asked you earlier!