Dinosaurs and Moustaches

Making paper from vegetables

I moved house, and my new flatmates were away. There was only one thing for it: to make paper from vegetables.

It was surprisingly hard to find instructions for the process on this, and there doesn't seem to be any books on the subject anywhere in Scotland. Pretty much everything you find online just explains how to recycle old newspapers, and doesn't shed any light on how paper is made in the first place.

With good local greengrocers, I set out to explore.

Ten leeks sitting in a sink

Ingredients came first and having no great idea about what would most suitable I bought ten leeks. The tops seemed like they should be quite fibrous since they are largely inedible, and frankly, I like them. Ten of these noble plants accompanied me home, ready to set forth boldly into the unknown.

A leek chopped into strips

Cut and soak

Whatever you plan on using, give it a good wash and cut it into strips a couple of centimetres wide.

I reckoned it was better to cut these leeks lengthways since that's the way the fibres seemed to run. Long molecular chains are responsible for the strength of plastic carrier bags and it seemed a good model to follow. Snapping a stem in two seemed to confirm that I wasn't talking complete rubbish.

A leek leaf snapped in two, revealing its fibrous innards

Job done, leave your plant material to soak in cold water for as long as possible and as least overnight: this will soften it up.

Two saucepans full of leek parts

Equipment

This is a good opportunity to sort out the equipment you'll need. My leeks ended up soaking for three days while I kept finding there were more things to lay my hands on and films worth seeing at the cinema.

Essential items are:

A mould and deckle are basically just two wooden frames of the same size; the only difference is that the mould has a fine wire mesh stretched across it and the deckle doesn't. It's easy enough to make a set from cheap pine about two centimetres wide and thick, which is what I did.

Work out the size you want your paper, cut the wood to the right size and get busy with a staple gun to hold it together. Make sure you give it a couple of thick coats of varnish since they'll spend plenty of time submerged.

I aimed to make a B5-sized mould and deckle, though it ended up a little smaller than that; an IKEA storage box served perfectly as a vat.

A bucket of chopped up leaks in caustic soda

Alchemy

Plonk your plants into the bucket and cover with water. Put your rubber gloves on and add some caustic soda to the water. I wasn't terribly precise about this, adding a fair amount but stopping before I thought I'd gone too far.

Stir it about with some sort of long-handled utensil that you don't really want to use with food again, and boil that bastard for about three hours!

Here comes the science: plants contain two sorts of fibrous materials, lignin and cellulose. Cellulose is good: it is tough and is the main ingredient in paper. Lignin reacts to light and if there's any in your paper, it will curl up and go brown before long. The caustic soda turns the water in the bucket alkaline, and this dissolves away the nasty old lignin.

If you've ever notice old newspapers go weird when they're left in the sun, that's because of how they're produced. They don't need to last long, so pulp for them is made by mechanically crushing wood, making use of about ninety five percent of the material, leaving in the lignin. But we want rid of it, and when it's ready, the bucket will be full of nasty black gunk.

That same bucket after three hours of boiling in caustic soda

When it's ready, pour it through the sieve and into the sink. Thinking that it might be a bad idea to pour caustic soda down straight into the pipes, I put the plug in and diluted it rather a lot first. You'll be amazed how much of the vegetables has dissolved away and how little pulp you're left with at the end.

Straining the mixture through a big sieve Pulp left when the liquid is drained off

Rinse the pulp thoroughly, whizz it in the blender, then transfer it to the vat, and pour in at least enough water to cover the height of the mould and deckle. Obviously, the more water you add, the more dilute the pulp will be and the thinner the paper. Stick your hands in and shake them about to make sure the pulp gets going and fills the vat.

A vat of water with pulp mixed in

Making paper

Hold the mould with the wire mesh facing up, and sit the deckle on top. Keep a firm grip on these and lower vertically into the back of the vat. Bring them forward until they're horizontal under the water line and pull them up.

As excess water filters down through the mesh, gingerly shake the mould and deckle from side to side to help the fibres get mixed up. When pretty much all the water has drained through, put the mould on the table and remove the deckle.

You should have a sheet of wet fibres sat on top of the mesh, ready to become a sheet of paper once it dries. But you don't want it on there, so dip some blotter paper in water until it's completely saturated. You're going to press or "couch" the sheet onto there. The surface tension of the water in the blotter is greater than the force holding the sheet onto the mesh, so the sheet is pulled down onto the blotter.

A cake of fibres sitting on the mould That cake turned out onto wet blotter paper

Turn the mould upside down and in one smooth motion press one side onto the blotter and roll the mould across. If it works, the mould will lift clean away leaving the whole sheet behind.

Leave the new sheet of paper to dry and repeat the process for as long as you have a reasonable amount of pulp left in the vat. When it's completely dry, you'll be able to carefully peel the paper from the blotter.

The resulting seven and a half dry sheets of leek paper

Results

After all that work, those ten leeks furnished me with seven and a half sheets of delicate, thin paper. It's rather nice, quite like tracing paper, and perhaps a bit too fragile to really be used. If nothing else, it's a great space saver since these don't take up half as much room as those leeks did.

But these were to serve as a prototype, and I've now got a better grip on the process. I didn't know all that stuff about lignin and can now see that leeks aren't the best plant to use since they aren't particularly high in cellulose. And I've now got a clue about the quantities of pulp to use and can see that I had rather a lot of water in the vat when I scooped out these pages.

Plenty of opportunities remain to make more in future.

Light shining through a sheet of vegetable paper