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:

Research

Collect materials

SAFETY FIRST...

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!