I'm not sure what's going on but the last two batches of homemade cashew and sunflower seed milks went bad faster than usual i.e. 1-2 days.

What can be added to make them last longer? Both artificial and natural preservatives are ok for me.

  • are you making this yourself or buying something prepackaged from the store? Commented Jul 19, 2017 at 2:44
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    Blender unclean and contaminating the product? Spoiled nuts or foreign matter in the raw material? Unclean containers? Fridge failing? ...How does it spoil anyway? Blanket preserving against an unknown spoilage reason is probably going to be hard without altering the taste drastically (eg by adding large amounts of salt, acid or alcohol).... Most neutral tasting things that kill anything that moves tend to know that you are also moving and alive. Commented Jul 19, 2017 at 13:44
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    Would pasteurization cause the milks to split? If not, try that, but make sure to put it into sterilized containers.
    – Joe
    Commented Jul 19, 2017 at 15:14
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    You might want to see this question as well, which suggests you can freeze it: cooking.stackexchange.com/questions/65929/…
    – Batman
    Commented Jul 20, 2017 at 3:53

2 Answers 2


This question has two facades:

  1. First get rid of the already-there spoilage microorganisms.

Before blending the nuts, I soak them in vinegar for a while and rinse thoroughly. And always using sanitized equipment and boiling the water (and sugar if you're adding) is quite a good practice to kill the microorganisms you might have in your ingredients.

  1. Prevent (or at least postpone) future spoilages.

If you have a sous-vide setup, using the lowest pasteurization temperature at 54C you can try to pasteurize. Please check some charts on this. It's hard to give an estimate without knowing your container sizes. Some nut-milk can handle acidity, some can't you can experiment with that as well.


Roast your nuts first in the oven. Use water that's been previously boiled. Ensure all containers and tools are sterilized. Add a pinch of salt.

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