🌿 European Alternatives to Kakishibu — Exploring Local Tannin-Rich Fruits

Earlier today a question came up in the Professional Natural Dyeing Course about Japanese kakishibu and whether there might be European alternatives.

Tannins are currently a hot topic in the course, as students have just begun working on their tannin portfolio this month. Naturally, the conversation quickly opened up into a broader exploration of tannin-rich plants and fruits.

Japanese kakishibu is the traditional tannin extract made from unripe Diospyros kaki fruit (persimmon). The fruits are harvested while still green and fermented to produce a liquid rich in tannins. Historically, this extract has been used in Japan for dyeing, waterproofing textiles and paper, strengthening fishing nets, and protecting wood.

A Forgotten European Fruit: Medlar

Medlar (Mespilus germanica) single fruit on a tree in autumn

During the research, one fruit kept appearing: the Medlar (Mespilus germanica), an old European orchard fruit that was once widely grown but is now relatively forgotten.

What makes medlar interesting from a natural colour perspective is that the fruit contains significant tannins when unripe, making it extremely astringent — not something you can eat straight from the tree.

Traditionally the fruit was harvested in late autumn and then allowed to “blet”. During this process the fruit softens and turns brown as the tannins break down and sugars develop. Only after this stage does the fruit become sweet and edible.

But before that stage, the fruit is notably tannin-rich — which makes it interesting to consider from a dye perspective.

Other European Tannin-Rich Fruits

While the chemistry of these fruits is not identical to persimmon tannins used in kakishibu, they highlight the wider landscape of local tannin sources that might be worth exploring.

Some of the possibilities that came up include:

• Crab apples — especially wild or cider varieties, which can contain noticeable tannins

• Medlar — an old orchard fruit with strong astringency before bletting

• Sloes — the fruit of Prunus spinosa, well known for their strong tannic bite

Another interesting possibility — though not a fruit — would be blackberry leaves, which also contain tannins and occasionally appear in traditional dye practices.

A Local Discovery

Interestingly, when I mentioned the medlar idea to Tristan, he immediately said that there are medlar trees growing nearby at the Irish Seed Savers Association — which is not surprising given their focus on heritage fruit trees, particularly apples.

Apparently we even had some medlar fruits sitting in a drawer a couple of years ago — quietly rotting away!

So this autumn we will definitely collect some fruit and run a few small experiments to see what happens.

As with so many things in natural dye work, exploration often begins simply by looking again at the plants and fruits growing around us. 🌿🍂