Trade secrets... Curdling of soya milk

Tofu

Source: Shutterstock

Secrets of the trade: Jonathan Hare asks why soya milk tends to form hundreds of floating lumps when added to coffee

Recently I bought a coffee and asked for it with soya milk rather than cow’s milk. At first it looked and tasted good; it was a hot golden brown liquid like every other coffee. However within a few minutes I was shocked to look down and see my lovely coffee had transformed into a watery-looking dark brown liquid with thousands of tiny lumps floating in it. The soya milk had curdled.

But why does soya milk curdle? Jonathan Hare investigates…

Thanks for using Education in Chemistry. You can view one Education in Chemistry article per month as a visitor. 

A photograph of a teacher standing in a white lab coat, speaking with a class of children in a laboratory, is superimposed on a colourful background. Text reads "Teach Chemistry means support for classroom and staff room".

Register for Teach Chemistry for free, unlimited access

Registration is open to all teachers and technicians at secondary schools, colleges and teacher training institutions in the UK and Ireland.

Get all this, plus much more:

  • unlimited access to resources, core practical videos and Education in Chemistry articles
  • teacher well-being toolkit, personal development resources and online assessments
  • applications for funding to support your lessons

Already a Teach Chemistry member? Sign in now.

Not eligible for Teach Chemistry? Sign up for a personal account instead, or you can also access all our resources with Royal Society of Chemistry membership.