Marcia Selsor’s Tips on Obvara Firing

Enhance the effects of an obvara firing by texturing the surface!

Finished pots fired with the obvara firing technique, by Marcia Selsor

Finished pots fired with the obvara firing technique, by Marcia Selsor

The obvara firing process, which originated in Eastern Europe around the 12th Century, involves scalding the finish on the pottery to seal the porous surface. Similar to the raku pottery process, a bisqued pot is heated, in this case to 1650°F (899°C) and removed from the heat. The difference is that the pot is then dipped into a specific obvara yeast mixture before being dunked in water to rapidly cool the piece. The effects are quite stunning.

In this post,  an excerpt from her video Raku Firing: Expanding the Potential of the Raku Kiln, Marcia Selsor shows how to enhance the effects of an obvara firing by texturing the surface and then shows the exciting process. – Jennifer Poellot Harnetty, editor.

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More on Obvara Firing

(from Marcia Selsor’s website)

The obvara firing technique is a technique originally used to seal low fire pottery. It is believed to have originated in Eastern Europe during the Middle Ages. There is a revival of the process underway in Ukraine and the Baltics. It is nicknamed “Baltic Raku.” The solution which I call the “brew” is a mixture of flour, yeast, and water. See the recipe here. It is mixed three days in advance of firing. Pieces are made and bisqued before the final firing. Using a raku kiln, fire a batch of pots to 1650 degrees F. Pieces are removed one at time, dunked into the brew and then quickly into water. Then they air cool. The brew burns quickly on the surface of the piece before going into the water. The water stops the burning and color change.

If the kiln gets below 1500F before al the pots are processed, turn the kiln back on and take it back to 1650F. It the piece is too cool the obvara firing process doesn’t work and makes a slimy mess.

To learn more about Marcia Selsor or to see more images of her work, please visit

**First published in 2014
  • John S.

    Hey Marcia:

    Great information here, thank you. I was wondering if when you’re dipping the vessels with small openings, do you put them into the brew upside down, or rightside up? Because if the small opening, the piece tends to retain more heat: so I’m more concerned with thermal shock. While trying to handle one of these pieces, I dropped it twice in the rinse, breaking party of the foot ring off. 😪

  • Vivi S.

    Hello! I am a first generation American born Latvian. I remember visiting Latvia in 1991 and seeing these types of pots in the rural countryside. How thrilling! Beautiful. I can’t remember what cone you fire your bisque? Would you please tell me? Doesn’t a more open clay body that is not vitrified absorb and create more beautiful patterns? BTW The Baltic States are considered Northern Europe and they are VERY far away from Siberia. Cheers, Vivi!

  • Phyllis F.

    I have sourdough starter. Why is this process using yeast? If it is so old yeast eas not invented?

  • I don’t know if i would wait two weeks to use it again, after a couple of days of fermenting that stuff gets ripe. I would not want to know what two weeks would smell like.

    • John S.

      I don’t know about two weeks, but I just completed a obvara firing using new that I was supposed to use a week ago, and it turned out fine. Try the two week old brew, and see what happens… after all, it’s only clay!! 😁

  • Subscriber T.

    How long is the mixture good for? If I want it to work, say 2 weeks later, would it still be good? Would I need to maybe keep adding a bit of sugar?

    • Marcia S.

      most say four days. Others try to revigorate the yeast by adding more. And yes it gets very ripe.

  • Katie T.

    Sitting here waiting for my kiln to reach temp. First obvara fire everything I know is straight from you

  • Ursula V.

    Love your work and that finish just moved to NC I do raku , would like to work with someone here if you have some suggestions please let me know. Ursula

  • Todd T.

    Has anyone ever tested obvara pots for food safety? Ive have found mixed results on this elsewhere on the web. Also would it work as well on a pot fired to cone 6 prior to the obvara to give the pot more durability?

  • Hilli J.

    It is a great Video, you made about Obvara firing technic. Since I used to do more in Raku firing technic, and happy to get new knowledge. You explained you used sodium silicate, is it the same like terra sig?? May I use Terra Sig instead?? I am planning to do it soon. Any other infos how to get the recipes?? Hilli

    • John S.

      Honestly, there can be many reasons. Are you trying to get the “color” on flat/ smooth areas, or on texture parts? Temperature plays a big part, and it is important to keep there brew mixed up and all the particulates in suspension.

  • Margrit S.

    Can anyone tell me if sodium silicate applied to a pot is harmful to the kiln or kiln elements (fired to cone 06 for a bisque and cone 6-7 for a glaze firing (electric kiln)? Is it like salt? Does it react with glazes?
    I work in a community studio.

  • Marcia S.

    Just rinse them well. there isn’t a residue unless it is severely under fired.
    I burnish smooth piece with Terra sig or use a highly textured surface which responds well to the obvara.


  • Stephani S.

    this should be a great video! Marcia has such a wealth of knowledge and experience, and she demonstrates process so well

  • Marcia S.

    I don’t use wax on Obvara either. I don’t even thing I could apply it to a highly textured surface. I am glad the Obvara technique is so widely spread. There is a really good link on Fabebook called the Obvara Firing technique. There are many there doing amazing work.

  • Anna T.

    As for me I wash the pots with a sponge. They don’t need to be covered with paste wax because they are sealed with obvara mix. Moreover I usually burnish the surface.

    • Victoria K.

      Marcia if you are out there. I need your help. I have a couple of pots where the obvara is starting to flake off, what did I do wrong?

  • Great video, I plan on trying obvara soon, I usually do raku and horsehair. My only question is what do you do with the pots after they cool? For raku and horsehair, I wash them with soap and a blue scrubber, then when dry, I seal the horsehair with paste wax. Do you ‘wash’ the obvara? Thanks, Joe

  • Marcia S.

    I don’t think the sugar is what causes the black but rather causes the yeast to ferment.Thanks for posting your variations. There are many. The milk idea is even in India.
    There is much research going on about obvara lately. Here is a link to my friend, Janice Chassier , who presented a session on the history of Obvara at the last NCECA conference after conducting research in Ukraine and Belarus.


  • Anna T.

    Great video. I made obvara several times. I added cup noodle (instant chinese noodle)and vegetable oil. As for me I don’t like the effect sugar produces, it gives too much black colour. Though it can be fixed reducing the temperature. Yes there are many recipes. The most peculiar one is a mix of used cucumber pickle and rye flour (I haven’t tried yet). Obvara is a traditional russian technique. Milk obvara is very popular.

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