When demonstrating I am often asked to explain the difference between the gums we cake decorators use. When making modeling paste I prefer to use gum tragacanth rather than its synthetic substitute CMC basically because gum tragacanth gives me a firmer paste and I find it easier to work with.
The proportions I use in the UK are 1tsp to 250g sugarpaste. Knead the gum into your sugarpaste and leave overnight to take effect (you’ll be able to start feeling the difference after a couple of hours)
The following information is from Wikipedia and confirms what I have always believed:
“Tragacanth is a natural gum obtained from the dried sap of several species of Middle Eastern legumes of the genus Astragalus including….. Astragalus tragacanthus. Some of these species are known collectively under the common names “goat’s thorn” and “locoweed”. The gum is sometimes called “shiraz gum, “gum elect” or “gum dragon”. The name derives from tragos and akantha, which means in Greek “goat” and “thorn”, respectively.
Iran is the biggest producer of the best quality of this gum.
Gum tragacanth is a viscous, odorless, tasteless, water-soluble mixture of polysaccharides obtained from sap which is drained from the root of the plant and dried. The gum also seeps from the plant in twisted ribbons or flakes which can also be powdered.
Gum tragacanth is less common in products than other gums, such as gum arabic or guar gum, largely because most tragacanth is grown in Middle Eastern countries which have shaky trade relations with countries where the gum is to be used. Commercial cultivation of tragacanth plants has generally not proved economically worthwhile in the west, since other gums can be used for similar purposes.”
CMC or Carboxymethyl cellulose, E466, Tylose – all the same thing
“Is synthesized by the alkali catalyzed reaction of cellulose with chloroacetic acid”
The beauty of using CMC in cake decorating is that it is more or less instant, so great for last minute requirements and class situations, however as stated above I do prefer to work with the real thing!!
Whilst at the Australian cake decorators seminar in Sydney a couple of weeks ago I learnt of a third product that is used in Australia. It is called ‘clear gel’ or ‘clear set gel’. It is basically Agar Agar a seaweed derivative and is used in much the same way as the above. I have been given a small packet to try, so I’ll let you know how I get on!!