Leather Drinking Vessel
One form of a traditional drinking vessel is called a Jack. It is a leather cup soaked/lined with beeswax to prevent the leather from getting nasty from your beverage. Leather vessels were also lined with pitch, which is something like pine tar. Pitch was good because it could withstand hot drinks. Beeswax not so much. Even leaving beeswax in the sun can make it melt. Sibylla and I tend to like our beverages, and we don’t like the taste of pitch. We tried beeswax but didn’t like how it cracked when squished and the effects of the hot sun on it.
We came across some cool class vases at a dollar store one day and decided to wrap those up in leather and see if we could make a decent looking medieval vessel. For those wanting authenticity, some drinking vessels were made from bull testicle sacs and these have a similar look. We will let your research that topic online.
These leather-encased vases are pretty tough. We have dropped more than a few in our day and most have survived.
The first step is to find a vessel that fits your hand and will hold at least a pint of beer! Trace the outline onto cardboard, and then trace that outline 1.5 times bigger. That will be your pattern. You will need to decide if you want a two-piece pattern where a ridge runs down the center of the bottom of the vessel, or a three-piece pattern where there is a flat circle at the bottom. We had more luck with two-piece. 
You will need to find a supplier of 4 to 6-ounce vegetable-tanned leather (veg-tan). Do some online searches and you may find a local supplier.
Trace the pattern twice onto the leather and cut it out with sturdy scissors.
These will seem big compared to the vase. Make sure they will ‘wrap’ around the vase before you start sewing. 
Soaking the pieces in water for a few minutes will make them wrap around the vase better. 
These will seem big compared to the vase. Make sure they will ‘wrap’ around the vase before you start sewing. These pieces shown also need the round flat bottom added. I like to use a leather punch and go through both pieces at the same time so the holes match up. 
Sew the one side with artificial sinew, then punch the other side and sew. You can also just punch both sides before you sew. Once you have sewed to the end, go back and sew to the other end. This is called a saddle stitch (if you go back to the beginning) or a hitch stitch if you use two needles at the same time. 
You will end up with something like this. Ideally, the entire mouth will be sewn shut. 
Some vases have flat bottoms, others have a seam. They both work. 
Leave a length of string dangling from the mouth. This is something you can hold onto when ‘boiling’ the vases. 
Submerge the bottle in 180-degree water for up to 180 seconds. You will see the leather shrink around the bottle. Keep in mind it will continue to shrink after it removed from the water. If you over ‘boil’ it, the seams will rip. A sign you should take it out is a slight darkening of the leather. You might want to test out a scrap piece of leather first to see how much it shrinks. Use a wooden spoon to keep it submerged and check it often. 
This one might be slightly overcooked. The leather will continue to shrink until it dries so keep this in mind. When you take the vessel out stand it upright and press down so the seam on the bottom gets as flat as possible. 
That seemingly loose bag gets pretty tight after boiling. This will continue to get tighter as it dries. We lightly cut/carved designs in these before hardening. 
Wait at least a day before trimming the excess off with a utility knife. Be sure to wait until it is completely dry. The ones to the left were trimmed too early and exposed too much of the vase. 
This drinking vessel is ready for some cord to be wrapped around the neck.
