Whilst methylcellulose does a wonderful variety of things, the defining ones, unique selling points if you like, are related to how it behaves in response to heat.

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Solubility

It is important, really important, to be aware that it is more soluble in water the colder it gets; and obversely, less and less soluble as the water warms up. The maximum temperature at which methylcellulose will dissolve (from powder to aqueous solution) is called the dissolution temperature. Each type will have different dissolution temperatures depending upon the substitution type and quantity; though the differences may be subtle, some are large.

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If you add methylcellulose to a hot liquid, it will not dissolve…ever, until it cools down. This is useful when making sauces, it provides no viscosity during processing, but not so good when making something that requires cold viscosity for forming, like a vegan burger.

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Hot Gelling Properties

Once it has dissolved, it will get thicker as it cools and thinner as it warms up to the thermalgelation temperature, when the methyl groups start linking up. This can be seen as a change from clear to white, combined with the phase change from liquid to gelled solid.

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When methylcellulose thermalgels, it always releases (squeezes out) a proportion of the water. This is called syneresis. The stronger the thermalgel, the higher the percentage of syneresis. This may be reduced by adding a cook up starch, an insoluble fibre or anything else that absorbs water when heated e.g. locust bean gum. However, reducing the syneresis reduces the succulence of products which may benefit from it.

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Note that the gelled methylcellulose (solid phase) is NOT a self-healing gel – so if you chop it up, it will stay broken up. If you allow it to cool back to a liquid then remix, it will be like you never chopped it up; it becomes a thick liquid again that thermalgels to a firm solid on reheating (provided you don’t chop it up again…)

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Meltback

The meltback temperature is found when the solid thermalgel turns back to liquid as it cools. This is generally close to the dissolution temperature and about 25-30C below the thermalgelation temperature. ‘Standard’ methylcellulose has a meltback temperature at the bottom range of mouth temperature, which can give it a soft gluey mouthfeel as you chew. It doesn’t synereses much either, so not so juicy. The supergels, like MX and MCE 100TS meltback well below mouth temperature, which means that they stay gelled when eaten and fracture when chewed releasing moisture – succulence.

 

Considerations For Selection

For the purposes of choosing the correct methylcellulose to work with, it is wise to consider:

• Gel strength and type required – strong, brittle, lots of syneresis – succulence? Or can you work with a firm, slightly more elastic thermalgel that does not synereses much?

• Dissolution temperature – can you cool your product down low enough to let a supergel dissolve? If not, then you need a ‘standard’

• Meltback characteristic – do you want it to remain gelled for as long as possible when cooling (avoid gluey mouthfeel)?

• Syneresis – some people want a vegan burger to ooze…er… blood. OK something that looks like blood – coloured, tasty water. The downside is it burns on in the pan and gives yield loss. So, for a ‘bleeding burger’ go for high syneresis. For a better yield and less sizzle, got for the standards.

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I did some work recently assessing the grades most commonly recommended for use in vegan burgers. I don’t have a method of measuring gel strength e.g. a gel tester, but the data below may help you decide which grade to try. Dow/DuPont/IFFs other grades, SGA16M, Bind 250 and Bind 112 can also be considered and each has their own benefits; that said, if you want to work with the Bind 112, get in touch with me or Dow first.