How to Make a WARM Mug

Each Tonfisk Design piece is handcrafted at our factory in Turku, Finland. However, we wanted to share with you how exactly each piece is made using our WARM mug as an example.

First, the clay is mixed on Friday mornings. The clay contains 4 basic ingredients: Feldspar, Kaolin, Quartz, and water. It’s a bit like baking a loaf of bread in that each ingredient needs to be measured and mixed exactly.

After the ingredients are all mixed into a thick liquid mix called the casting clay they are placed in the storage vat for the weekend where the clay is continually stirred slowly to allow the air to rise.

On Monday mornings we begin our week’s production schedule. The molds of the required production are placed on the casting tables. Each mold is made of plaster. We have varying amount of molds per products. The casting clay is then poured into the molds one row at a time. The clay is allowed to sit in the mold for roughly 15 minutes during which time the clay particles which are beside the wall of the plaster mold begin to stick together as the plaster mold sucks the water from the clay.

After 15 minutes the mold is emptied of the excess clay and then left to rest upside for 15 minutes before being turned over after which it is left for another one and a half hours to allow the clay inside to dry enough before the mold is opened and the pieces removed and placed very gently on shelves. The cup is very delicate and needs to be handled with special care.

Once the clay is dry, the next stage can begin.  Using a sponge and cold water, the cups are wiped down several times to remove any imperfections that may have happened during casting. Once the cups are nice and smooth, they are put into the kiln for their first firing called a bisque firing.

Simply put, a bisque firing is the first time newly shaped clay goes through a high-temperature heating. The high temperature changes the molecular structure of the clay so it hardens and removes all moisture but remains porous. This will the glaze to adhere to it.

The next step is glazing. Ceramic glaze is a coating applied to bisque ware for the purpose of coloring, decorating, and/or waterproofing a piece. It is the glassy layer on the outside of the cup. A layer of glaze is applied to the bisqueware and left to dry before going back into the kiln for the glaze firing. Our porcelain is fired to 1250 C.

Once dry, the glazed pieces are carefully loaded into the kiln for glaze firing. The glazed pieces cannot touch each other or else they will fuse together permanently. The kiln is slowly raised to temperature and then dropped until cooled completely. Once the kiln is completely cooled, the pieces are unloaded.

After each WARM mug receives its wooden sleeve, it is ready for packing and shipping! We ensure that each piece is packed carefully so it does not break during the delivery process. We will even giftwrap your order at no extra cost if needed!

If you have any questions about our production process, packing, shipping, and more, don’t hesitate to contact us at and we will get back to you as soon as possible!

Thank you for your continued interest and support!

How to Make a WARM Mug


We ship from Finland to almost anywhere in the world.


Options include Paypal, Apple Pay, Credit cards, Finnish Banks, Klarna

Gift Wrapping

Want to send as a gift? We can Gift Wrap your order at no extra cost.

Careful Packaging

All deliveries are packaged extremely carefully so they arrive in perfect condition