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When chopping garlic the blade of my knife, and any fingers used to handle the garlic, become sticky.

What causes this reaction?

Is there any way to counteract it?

EDIT: After trying both suggestions out on my own, olive oil worked best for me. This feels very much like a results may vary situation, so I encourage anyone curious to try both ways.

  • Garlic juice is supposed to be sticky, that's how you get the gold leaf to stick to the parchment! :) – Marti Apr 3 '12 at 16:01
  • I can't answer the Why that others have answered so well, but when I chop garlic I just dribble some water on them. It prevents the stickiness without adding oil, salt, etc. – Carey Gregory Dec 11 '12 at 2:14
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Garlic is full of sticky (and tasty) oils, which is what makes it stick to your knife and fingers.

Dipping your fingers in olive oil and carefully rubbing them on the flat of the knife blade should prevent the garlic sticking.

  • Hm, are you sure it's oil? It washes off easily with water, and wetting the knife with water prevents sticking too. – Cascabel Apr 2 '12 at 16:21
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    Not to mention that oil generally doesn't cause sticking, it prevents it. I might guess that it has to do with fructooligosaccharides, a naturally-occurring sugar in garlic. – Aaronut Apr 2 '12 at 17:48
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    +1 for fructooligosaccharides. Did you comment just so you could type that, @Aaronut? :) – JoeFish Dec 11 '12 at 15:08
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When crushed or chopped, garlic releases mercaptins from within its cells (sulfur containing compounds). Sulfur readily forms bonds with other amino acids, notably cystine which itself contains a sulfur atom in its chemical structure. When two sulfhydryl groups (S-H) come into close proximity, a disulfide bridge can be formed, creating a relatively strong chemical bond between the two molecules. This chemical attraction between the proteins in you skin and the garlic compounds causes the sensation of stickiness, much like hydrolyzed sugar sticking to your skin. Since lipids (oils) have a stronger attraction to the oils that coat your skin, they displace the sulfurs and prevent your hands from being sticky.

When garlic is roasted, the proteins within are denatured (lose their function) and lead to a milder taste and less sticky chemicals.

  • Really informative and useful first post. Welcome to the site. – spiceyokooko Dec 10 '12 at 21:37
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You can prevent it from sticking by wetting the knife - just quickly run water over it on each side.

I'm fairly certain that Aaronut's right that it's a sugar (what else would it be?) but I don't know for sure. I'll update my answer if I can confirm it!

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