Wheat paste is used in bookbinding to glue the end-pages to the inside of the cover. This process is called casing in. To make wheat paste all you need are wheat starch and water. I bought my wheat starch from Talas, but you can get it from specialty food stores as well. The first time I ever made wheat paste I actually used regular flour. This works, but you do end up with a better product if you use refined wheat starch.
To make the paste you mix 1 part wheat starch with 4 parts water. Here I used 1 Tbsp wheat starch and 4 Tbsp’s water. I find it is better to make small batches when I need it because it does go bad after a while. Whisk to remove lumps and let sit 1 hour.
Now it is ready to cook! I placed this bowl over a pan of boiling water to make a double boiler. This helps prevent it from burning and forming lumps. The package from Talas says to cook it for 15-25 minutes until it turns thick and translucent. However, mine usually turns thick and translucent after only about 5-7 minutes. Make sure to stir constantly because when it starts to thicken it is fast, and lumps can easily form.
Let the paste cool, then strain into an airtight container. To use, mix with a little water to achieve a creamy paste. Store in the fridge if you have extra leftover.