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Last night I mixed some peanut butter (consisting only of peanut and peanut oil) with some orange zest and raisins. After adding the orange zest the peanut butter became too dry to my liking so I gave the orange a good squeeze. Much to my surprise the peanut butter became even dryer!

I tried searching this online but failed, I presume because I don't have the slightest clue which attributes of the peanut butter and the orange are at play here.

Why does peanut butter become dry when mixed with orange?

PS Adding a couple of tbs's of extra oil fixed it and thankfully the raisins caused no extra surprises. I have some yummy but slightly dry peanut butter in the cupboard.

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    I've noticed the same thing when making tahini sauce. If you add the water slowly, you'll see the paste appear to get drier and thicker, and then thin out again, as you add more water. You can see this happening in this video, after the water is added at 1:52: youtube.com/watch?v=zgxxqSPa4Fs&t=131s
    – Juhasz
    Aug 12 '21 at 19:41
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Peanut butter is a suspension of ground peanuts meal in oil. Adding water (juice is a water based solution...) to that would cause a phase separation of the oil and water. I suspect that during this process, the oil will generate a bunch of fine droplets that can no longer hold the peanut meal in suspension, and result in it crashing out and becoming a dry mass.

One way to prevent this would be to stir small amounts of the water into the oil to create an emulsion. This is similar to the process for making mayonnaise, where the emulsion is between oil/egg yolk and an acidic water based solution, often vinegar or lemon juice.

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    Like water for chocolate
    – Willk
    Aug 13 '21 at 2:09
  • @Willk exactly like that.
    – bob1
    Aug 13 '21 at 2:45
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    the term for this is 'seizing', if anyone wants to do further research
    – Blargant
    Aug 13 '21 at 3:44
  • In my lingo we say the peanut flour gets hydrated. When dry peanut flour suspended in oil meets water, the flour hydrates and forms a thick peanut dough. Add more water and you'll get peanut batter. That's why peanut butter will suck the moisture out of your mouth if you eat it off a spoon. Same idea as this answer- just a different form of expression. :)
    – kitukwfyer
    Aug 13 '21 at 3:51
  • Peanut butter behaves like tahini (sesame "butter"). Adding water is the way to go.
    – Morts
    Aug 18 '21 at 12:48

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