It's fairly easy to find konjac (a. k. a. glucomannan, konjac flour, konjac powder, konjac gum, konjac glucomannan, konnyaku). It has a thousand year history in Japan and has been used for medicinal reasons due to it's dietary and health-improving qualities. Shiritake noodles are made from it. So are konnyaku yam cakes. It has a texture that I have come to love in the last few years.
But then Wylie Dufresne said he used it in conjunction with xanthan at the 2007 Star Chefs ICC to make his knot foie dish. I also have the chapter on konjac in "Thickening and Gelling Agents for Food" by Alan Imeson to use as a guide. What an amazing product. For the last couple of days, I have been intoducing myself to it in the free moments.
So, after walking a mile for an inch of understanding, this is what I know so far...
I worked with water based gels made from 3 ratios of konjac and xanthan.
The first gel is with konjac alone. I started with the recipe on the bag which was 1 level tsp to 8 oz liquid (translated to a 1.2% konjac mix).
A straight mix (blended at room temperature) yielded a fluid gel with a very slimy texture. Clarity was great. Adding a factor of heat increased the viscosity very slightly. The only similar texture from my experience would be pectin.
The next logical step was a 1% solution made with .5% konjac and .5% xanthan.
The room temp blend was slightly fluid with a nice palatability... none of the sliminess. Once heated, the gel loses it's nice mouthfeel and becomes very rubbery.
The last blend was taken from the Alan Imeson book which is 1% xanthan and .1% konjac (actually, he calls for slight konjac increases starting at .02%. My little Escali scale only measures to the tenth of a degree, so the best I can attempt here was .1. Even that is a struggle in accuracy as the scale sometimes jumps from .0 to .2 with no in between.) This is supposed to yield a synergistic thermoreversible gel.
The gel is very fluid with hardly any noticeable change from heating. This is a good example of how synergy works and why the point in between A and C is not always B. Many factors can influence the end result... including what type of food is being gelled. Imeson states that this ratio works in a solution with salt present (I can't remember the exact salinity... maybe .025% salt or something else very low). By adding a little sea salt to this same ratio and heating, the texture changes from a fluid gel to a set gel.
This gel can be cut and lifted at room temp, but unlike the unpalatable rubberiness of the heated half xanthan and half konjac blend this set gel has a great mouthfeel. It almost immediately begins to break down on the tongue.
The gel above here is the same ratio, but without the salt. I even spilled it trying to move it due to the fluidness (or fluidity?) of it. This is a great point in how different foods react differently with hydrocolloids. Many chefs want consistent ratios or formulas to incorporate into their dishes that will work on any food all of the time. This is not going to happen. Depending on the application, you cannot avoid the experimentation. You may get lucky, and the only thing the above information offers is a 'starting point.' Sometimes that's all you need.
How about adding salt to the other ratios above... there was no noticeable change in either of them. Another lesson in synergy.
I guess it's a moot point to show photos of some of these gels. Again, it's difficult to describe texture in words and sometimes even in pictures. I suggest just making some of these in your kitchen and experiencing the differences on the tongue... there is no other way to really judge palatability except by actually eating.
