Obvara is an old Eastern European firing method that I learned in Belarus in 2009. The work is taken from the kiln from 700 - 900C depending on clay and thickness of work, and plunged into a yeast/flour/water mixture and then immediately into cold water. It is an organic-like purely decorative finish.
The work should be bisque fired to around 1000 C. I find a pale coloured raku clay works best - though when in South Korea people did use a porcelain clay which withstood the thermal shock and worked very well. Also some people use coloured slip before bisque firing as a background colour.
I do not usually burnish my work but there are some lovely effects using a burnished terra sig finish.
I then fire the work in a raku kiln to around 850 C / 1550 C - the temp can vary depending on thickness and weight of work and your kiln and thermocouple readings - you might need to experiment a bit to get the temp to suit your work and the finish you require - and then dip the work into the obvara mixture and immediately into a bucket of cold water which stops the mixture 'cooking' and sets the pattern.
If you don't like the pattern the piece can be re-fired as the obvara pattern burns off.
This is my version of the obvara liquid:
Mix 1 kg flour / 1 or 2 sachets dried yeast / 1 tablespoon sugar and 8 - 10 litres warm water - leave covered in a warm place for 3 days, (though in warmer countries it seems to work sooner) - stir frequently.
Thanks to a Facebook Page, Social Media has helped preserve an ancient technique that was in danger of disappearing
The images below show various aspects of the technique and examples of finished work
Top: Poster for one of the workshops in India in 2017 / Dipping in the obvara mixture / Dipping in the cold water
Middle: Taking work from a traditional kiln in Rajasthan, India / Workshop in Australia / Workshop participants in Pune, India
Bottom: Results in Barcelona 2016 / 3 Obvara Forms / Obvara Form