A visitor has left a nearly full bottle of soy milk in our fridge. Personally, I hate the taste of soy milk, I find it too sweet and nutty for me, yet I feel compelled to use it up somehow.

I am going to make a bechamel sauce for a lasagne, and wondered whether I could use 1/3 soy milk and 2/3 regular milk in an effort not to waste the soy.

Will this still taste like soy?? Should I reduce (or increase) the ratio of soy? Will it affect the thickening of my bechamel, or the general texture of the sauce? I will be adding a bit of grated grana padano to the sauce at the end of the cooking process.

I did a bit of searching online, but everything was about a 1:1 substitution rather than the EFFECT of incorporating soy. Advice appreciated.

3 Answers 3


If the soy is "sweetened", I would not suggest using it in a savory sauce. However, if it is unsweetened, it should be ok. I personally like soy, but it all depends on the brand, and whether full fat, sweetened, plain or vanilla as to how I would use it. You might try baking with it, perhaps muffins, cake or biscuits - and substituting the soy for whatever liquid you would otherwise use.

  • 1
    Quite the opposite: Truly unsweetened soy products tend to require some sweetener added if substituting for dairy products 1:1 in savory dishes... May 5, 2015 at 9:30

I decided to test it anyway, so here are the results of a bechamel using 1 part soy to 2 parts regular milk:

Taste: There was nothing on the label to indicate the soy was sweetened, so I went ahead as if it were unsweetened. However, the sauce was much sweeter than usual, and on checking the ingredients, I note that there is 2% raw sugar (as well as 1% salt). So I guess it was sweetened after all! I added an extra onion and more salt to try to counteract the sweetness, but it was still noticeable to me. My husband said it was fine.

Texture: In the first stages of adding warm milk (infused with onion, bay leaves and peppercorns) to my butter/flour, I noticed that the roux was a lot stretchier than normal, so I had to add milk more frequently. Otherwise, the overall texture was lovely, very silky.

Thickening: It seemed to thicken a bit more than usual, but this may have been subjective. It wasn't enough of a difference to affect the use of the sauce in any way. It certainly stuck to the bottom of the pan more than usual :(

Overall: If I were sure that I were using UNSWEETENED soy, I would try this again if I was again left with soy milk in the fridge. I would reduce the ratio to make 1 part soy to 3 parts regular milk for my personal taste. I added some Emmenthaler and Grana Padano to the sauce, but if using soy milk, I believe the Emmenthaler is too sweet, and should be replaced by a sharper cheese such as Cheddar.

Hope that helps others faced with the same problem.

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    Thanks for the follow up! Interestingly 2% is not far from the sugar content of cow's milk. Of course that's lactose instead of sucrose so the sweetness wouldn't be the same. Jun 10, 2011 at 12:52

I use soya milk because it fits into my wife's diet. In most cases it is hard to tell it is in a sauce.

If the soya milk is unsweetened it should work OK in any sauce that starts with making a roux. Add onions and it is almost undiscernable until after the meal.

However, if the plates are not washed promptly, the sauce often sets very hard and is difficult to wash off without soaking!

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