How long should I keep minced garlic in lemon juice?

Question

A problem that I sometimes encounter when making dressings or tahini hummus is deciding how long I need to soak garlic in lemon juice after mincing it.

For context, there are several reputable publications on the internet which claim that this step makes the garlic less pungent in the final dish. (See https://www.seriouseats.com/israeli-style-tahini-sauce-recipe, and https://www.arkansasonline.com/news/2013/jan/23/lemon-juice-defangs-garlic-20130123/) Having tried out this technique myself, I can verify that it does exactly what is promised: The garlic is mellow and subdued rather than overpowering in my dressings and in my hummus.

My question pertains to the minimum length of time necessary to achieve this effect. Currently, I pour the mixture into a cup, cover it with cling film, and keep it in the refrigerator overnight. I'm almost certain that this is way longer than necessary, but I can't bring myself to change my recipes without actually knowing the true value and, more importantly, why this is so. I reckon it has something to do with the enzyme 'alliinase' which occurs naturally in garlic.

Answer 1

There is no need to give it time; the few seconds the garlic spends in the lemon juice while you're figuring out what goes in next is already enough.

The thing here is that the acid isn't making the garlic less pungent; it's making the garlic get pungent (much) more slowly after its cell walls are ruptured by being minced or crushed.

The intact garlic cell contains a number of precursor chemicals, amongst them alliin, which aren't particularly strongly flavoured compared to allicin (note the C) which is the compound responsible for most of garlic's famed pungency.

When the garlic cell is damaged and the juices inside are exposed to oxygen, the alliinase enzyme mentioned in your question gets to work converting the alliin into allicin; however, the enzyme needs to be in a certain pH range - not too acidic, not too basic - or it will be rapidly denatured, which will prevent it from doing its thing on the alliin. So, by soaking the minced garlic in acidic lemon juice immediately after mincing it, the alliinase has only a short period of time to produce allicin before the acid gets to it and more-or-less stops the process.

As such, there's no need to leave the garlic in the lemon juice for any significant period; indeed, even in the lemon juice the garlic is actually slowly getting more pungent; your takeaway here is that the main thing that matters for how pungent the garlic gets is time between damaging the clove and soaking in acid. The amount of time that the garlic spends in the acid is largely irrelevant.

As an aside, heating will also denature the alliinase and to a significant degree convert the allicin into other compounds with different, 'cooked-garlic' flavours, which is why this technique is mostly seen in recipes where the garlic is used raw.