Mirjam Kotar 0 Report post Posted September 7 (edited) Dear all, i hope someone can help me. I try to do a porous porcelain with yeast foaming technique. I did search clay forums and archives and I couldn't find anything. There are some articles on this techinque in industrial ceramic field. I studied an article by R.L. Menchavez in Journal of Material Science titled Red clay-based porous ceramic with pores created by yeast-based foaming technique. And some other articles... the procedures seemed quite straightforward. So I made a mixture of 50% porc +50% water, to this I added 15% potato starch. Then yeast : I did 3 samples from 11 to 30 % yeast in relation to starch weight. I also did two experiments: yeast mixture directly to porc mix, and second with yeast that was risen separately. NOT ONE of 6 samples has risen. Any suggestions what and how to do it? Thank you, regards, Mirjam The picture is not mine, this is my goal ... if I survive all this yeast smell... Edited September 7 by Mirjam Kotar Quote Share this post Link to post Share on other sites
liambesaw 1,565 Report post Posted September 7 Maybe try different consistencies? 1 Hulk reacted to this Quote Share this post Link to post Share on other sites
Mirjam Kotar 0 Report post Posted September 7 (edited) In the above procedure I followed Menchavez recipe 50/50. Which way you suggest: more porc or more water or more starch? Or you mean more yeast? Edited September 7 by Mirjam Kotar Quote Share this post Link to post Share on other sites
liambesaw 1,565 Report post Posted September 8 I just meant try with less water and more water. The thing is, without gluten I don't think it's going to rise like dough, it will just become carbonated, the bubbles will pass through the clay and pop on the surface. An easier method may be to mix a surfactant and carbonated water with clay so it can be use immediately. I've seen some posts where people made a bubbly slip and applied it to greenware. Quote Share this post Link to post Share on other sites
Hulk 351 Report post Posted September 8 Hi Mirjam! I'm not seeing any pictures associated with your post. Any road, are you certain the yeast is viable (does it "proof") in the typical kitchen sense? Yeast added to warmed water (~100F/40C) spiked with some sugar should begin to foam within ten minutes or so. That seems like the easiest thing to cross off; once you're sure the yeast is live/good, perhaps a next step would be to determine if porcelain kills the yeast? I'm fairly certain that the mid fire stoneware I'm using supports microbial life, heh... Likely you'll want to keep your samples warm. Keep the dough warm for a faster rise; keep it cool if you wish to go sour. Quote Share this post Link to post Share on other sites
Mirjam Kotar 0 Report post Posted September 8 Yes, my yeast was alive, I tested it first normal way as for bread. And I did everything with warm water and kept everything around 40 °C. Sorry, it seems I didnt post the picture. This is my goal. Quote Share this post Link to post Share on other sites
neilestrick 3,343 Report post Posted September 8 The 50/50 mix will likely need to be adjusted. If your yeast is definitely alive and gasses are being formed, then it's possible that it's too runny and the bubbles are just passing through. It needs to be stiff enough that the gasses are trapped. If you're not getting bubbles, then either the mix was too hot and you killed it, or there wasn't enough food for them, which means you need more starch. My gut feeling is that 15% starch would be so dispersed throughout the porcelain that the yeast wouldn't be able to feed very well. If more starch negatively affects the structure of the porcelain, I would try adding sugar or honey, which would dissolve in the water and be readily accessible to the yeast. Quote Share this post Link to post Share on other sites
Mirjam Kotar 0 Report post Posted September 8 Ok, thank you, I will try tomorrow with more samples. My mixture was not stiff, was very runny, so I will add more starch. And in some I will add flour, and in some sugar. Will report back what happened. Quote Share this post Link to post Share on other sites
Magnolia Mud Research 591 Report post Posted September 8 Seriously consider using less water to thicken the slip along with the increased starch. Quote Share this post Link to post Share on other sites
oldlady 2,339 Report post Posted September 9 mirjam, may i ask why you want to do this? what is your ultimate goal? Quote Share this post Link to post Share on other sites
Mirjam Kotar 0 Report post Posted October 8 I have this picture in mine mind of a rough volcano pedestal in black (foamed black porcelain) with paper thin white porcelain bowl on top... just want to try foaming porcelain, actually. I always try to do something impossible :( last week I tried several samples more thick but no success. Quote Share this post Link to post Share on other sites
Min 2,278 Report post Posted October 8 @Mirjam Kotar, is the piece in your image above made using this technique? It looks a bit like it could be from a slip saturated piece of open sponge thats been fired, perhaps that could be an alternative way of doing it. Quote Share this post Link to post Share on other sites
Babs 901 Report post Posted October 8 Normal clay lave glaze work for same visual Quote Share this post Link to post Share on other sites
Mirjam Kotar 0 Report post Posted October 10 (edited) Yes, I know lava glaze gives you the same surface, but I would like to have a structural porous piece. And I did a piece with a sponge, looked kind of what I planned. However I'm stubborn and I want direct foaming with yeast :):):). Edited October 10 by Mirjam Kotar Quote Share this post Link to post Share on other sites
Mirjam Kotar 0 Report post Posted October 10 Now I found an artist Tiger Wong Ho Lun who seems to do similar technique. Will see if he is willing to share the idea, technique .... Quote Share this post Link to post Share on other sites
Babs 901 Report post Posted October 11 19 hours ago, Mirjam Kotar said: Yes, I know lava glaze gives you the same surface, but I would like to have a structural porous piece. And I did a piece with a sponge, looked kind of what I planned. However I'm stubborn and I want direct foaming with yeast :):):). Well keep trying. Post results please:-)) Quote Share this post Link to post Share on other sites
Marcia Selsor 1,785 Report post Posted October 12 Interesting affect. Marcia Quote Share this post Link to post Share on other sites
Tyler Miller 435 Report post Posted October 18 (edited) Ugh. What’s the point? Edited October 18 by Tyler Miller Quote Share this post Link to post Share on other sites