Konjac (Konnyaku) is a plant of Araceae family. It has long been edible in certain areas of Asia. Its raw tuber is called "konjac-Imo" in Japanese. Konjac-Imo is powdered, and when alkaline substances (lime, sodium carbonate, etc.) are added after boiling, it becomes jelly-like konjac.
The component of konjac is a kind of polysaccharide called “glucomannan”. It’s a water-soluble dietary fiber that absorbs water and swells. The molecular weight is estimated to be about 600,000 - 1100,000.
Konjac powder itself is odorless, but when dissolved in hot water it generates distinctive smells.
In 2013, Faris Nasir reported the function of konjac powder as a polymer, but since then there have been no notable reports. Verification began again in 2021, and is still underway.
- Uroshi-Pond is verifying the bubble solution using konjac, and reproducibility has been confirmed by at least one reliable source.
WHERE TO FIND IT[]
Jelly-like konjac is sold in japanese food stores, and on rare occasions konjac powder is sold as a material for DIY konjac. (It’s a simple powder. Contains black grains, which is konjac-Imo peels. It does not dissolve in water, but does not seem to affect the bubble.)
In Japan, peoples can buy it at a natural food store (organic food store), or it's available by mail order. (The author uses a simple one that 150 grams, about $ 11. https://item.rakuten.co.jp/ookahara/10000001/)
It’s sold as “Konjac powder” or “Glucomannan powder” on Amazon.com or ebay. But the author hasn't tried them, so their effectiveness has not been confirmed. (Please report if you have tried them).
(Added September 2022) Glucomannan powder appears to be an effective polymer. See the following blog for more information.
https://soapbubble.fandom.com/wiki/User_blog:Uroshi_Pond/Test_for_glucomannan_powder
USE[]
Faris reported that, as a primary polymer, 0.7 grams per liter of water seems the upper limit. As of May 2021, Uroshi mixes the solution with following recipe.
・ 3.4 grams konjac powder
・ 1,000 ml boiled hot water
・ 3,834 ml tap water
・ 262 grams detergent (Japanese detergent "Cucute")
・ 0.1 gram citric acid
1. Rotate 1,000 grams of boiled water with a stirrer.
2. Add konjac powder little by little.
3. Stir with a stirrer for about 40 minutes. If the rotation speed is low, the viscosity may increase in the middle and the liquid may stop rotating. Observe from time to time and adjust the rotation speed accordingly. (When stirring manually, continue stirring for 1 minute every 4 minutes for 40 minutes.) When the viscosity is high enough, stop the stirrer. (at this point, it may be thick and look like there are lumps, but they disappear after letting them rest overnight.)
4. Add this solution to 3,834 ml of tap water.
5. Add detergent.
6. Add citric acid.
7. Let it rest overnight.
(You may think that amount of citric acid is not enough, but in author’s environment the pH is stable at around 7.4-7.6, which may be because Japanese detergents and tap water have low pH. Adjust when using Dawn or other detergents.)
Note that konjac solutions are significantly less viscous than other solutions (such as PEO). Even with low viscosity, konjac solutions perform well.
(Added July 2022) In the past, baking soda was added to the above recipe. Recently, I have excluded the baking soda. The baking soda speeds up the thickening, but I have had a few instances of lumps forming.The solution can be mixed successfully without the baking soda.
EFFECTIVENESS[]
bubbles made by konjac solution
bubbles made by konjac solution
bubbles made by konjac solution
When used at the appropriate level, it can be very self-healing and produce giant bubbles even on a par with PEO or HEC. As far as the author knows, it is usefull natural polymer comparable to guar gum.
