(same with tahini)
In: 1
Sorry, why are you adding liquid to peanut butter?
You’re initially forming an emulsion (which is thick, like mayonnaise).
Peanut butter and tahini are a bunch of solid seed bits (peanut or sesame) in oil. Plus, usually, a bunch of emulsifiers to keep everything nicely suspended and prevent separation.
When you introduce water into that and start stirring the emulsifiers grab it and make an emulsion (a suspension of small water droplets in oil). This thickens the fluid phase just like how mayonnaise (water-in-oil) or salad dressing (oil-in-water) is thicker than either water or oil alone. Combined with all the solids, that makes things really thick locally where the emulsion formed.
As you mix it in more the the emulsion spreads out (and may break), and the extra volume of water you’re adding eventually dilutes everything down and back to the normal thin consistency you were expecting.
I’m not sold on the top comment emulsification explanation, especially if you’re using single ingredient PB. I don’t believe there are any emulsifiers in single ingredient PB, but adding either water or soy is going to change the polarity of the mixture, causing the hydrophobic proteins to change their shape (conformation). By inducing the more polar portions of the proteins to be exposed, you increase the bonds between them (proteins are VERY sticky), and the mixture appears to get thicker.
Latest Answers