Why Does Garlic Turn Green When Cooked
When garlic is cooked, the sulfur in the garlic reacts with the metal in the pan to form a green compound. This is perfectly safe to eat, and many people actually prefer the slightly milder flavor of green garlic. If you don’t want your garlic to turn green, you can avoid using metal pans.
There is at least one place in the world that intentionally turns garlic jade-green. When pickling or cooking garlic, sometimes it turns turquoise or blueish-green. The turning causes you to think the garlic is turning green or blue. If you notice your cloves of garlic turning green, that does not necessarily mean that it is toxic.
Even if there are no acidic ingredients in your recipe, it is very possible for your garlic cloves to turn blue in color as time goes on. Smaller pieces of garlic are most likely to turn blue, but whole cloves can change color, too. Heating the garlic, or mixing it with acid, may trigger the blue-green colour.
Garlic may become blue or green when exposed for long periods of time to any acidic ingredients, such as lemon juice or vinegar. If raw garlic is picked before it is fully grown, and has not been properly dried, then it may turn an iridescent blue or green when exposed to acids.
Sometimes, the sulfur in Garlic reacts with this and turns garlic green or a slight shade of blue. When a compound made up of sulfur interacts with copper, it turns to copper sulfate, which turns the bits in your garlic green or blue (think old pennies or Statue of Liberty). Garlic contains sulfur compounds that can react with copper to create copper sulfate, which is a blue or light-green compound. Garlic turns green due to natural sulfur compounds and the amino acids that it contains.
This is because, with older garlic, enzyme break down is more rapid, leading to faster reactions with the sulfur, which ultimately causes the garlic to turn green. Mature or older garlic typically means natural enzymes and chemicals are breaking down, making it more susceptible to reaction with sulfur and turning green.
The colour changes are caused by the reaction of enzymes with the sulfur-containing amino acids in garlics enzymes (the same enzymes that are responsible for the garlics flavour). The change in color, in turn, changes perceptions of the garlic consumption due to the chemical reactions of the various amino acids.
The shade of blue occurs when the enzymes and amino acids found in garlic react with a sulfur compound that is responsible for the pungent odor of garlic. Green is likely a result of the reaction of the sulfur compounds with the amino acids (building blocks of proteins) that are naturally present in garlic.
The natural sulfur present in garlic interacts with these enzymes, sometimes turning it a little green or blue. As with green garlic, the precursor chemicals, such as amino acids, interact with one another, which makes a big difference to garlics flavor and aroma. In turn, this has positive effects, since reactions are found in chemical precursors, green garlic usually has stronger flavors.
That is why a lot of recipes choose to use green garlic, especially when you want strong garlic flavor in the food. Do not mince the garlic together with the raw onions, because those have these characteristics too, which may cause a blue-green colour.
Cooking onions and garlic together may cause a color shift in garlic. If you have garlic that is susceptible to turning green, cook it over high heat to turn off enzymes. Sweating garlic or boiling it at relatively low temperatures will result in a rapid turn of green.
Garlic that has been blanched or is half-cooked by low-temperature boiling is most likely to turn color. Garlic also turns green (develops chlorophyll) when exposed to a change in temperature or exposed to sunlight.
Garlic bulbs will change from white to a yellowish-green color when the garlic is cooked. Garlic that has turned blue or green when marinated or cooked is completely safe to eat, and the presence of the color has no impact on garlics taste. Because these blue-green compounds are created from the same chemical precursors that make up the aromatic compounds, your sense that garlic that has turned green has stronger flavors than garlic that stays white is accurate.
Older garlic will have built up larger amounts of chemical precursors than fresher garlic, so both the region where you purchase garlic and the particular market where you purchase it may influence the likelihood it is likely to create these blue-green compounds. In specific cooking conditions, these compounds (aided by enzymes) will interact to create new molecules, giving the garlic its green color. As the garlic ages, two molecules called allyl sulfides are broken down to produce other chemicals, which lose odor and taste. Sulfur compounds called thiosulfinates are responsible for the health benefits of garlic, but they are also toxic when consumed in high amounts.
Green garlic contains a sulfur compound called allicin, and allicin is the active ingredient in garlic. The acidity causes a rearrangement of molecules within a clove of garlic.
Then, one day, the garlic turns bright blue-green, or even aquamarine or teal, turning the familiar dish into a strange mix of coloured accents, undermining the familiar tones that we expect. When you place garlic into vinegar-based pickles, it will often turn a green or blue. In fact, in China, where the pickled garlic called Laba is coveted for its green and blue colors, the garlic is left for several months to add to its color.
If you want to avoid the blue garlic, using fresh garlic is the best option, says LaBorde. Here are ways to make sure that your garlic keeps the natural color.
If the garlic is stored at room temperature, the garlic will break down slowly. This breakdown happens rapidly if garlic is stored cool. If you let the garlic sit for long periods, the sulphur turns to sulphuric acid gas (H2SO3). Raw garlic contains an enzyme which, when unactivated by heat, reacts with traces of sulfur (in garlic) and copper (from water or the pot) to create a blue copper sulfate.
LaBorde and Lopez-Alt also point out that older garlic is more likely to turn green, since it is likely to have larger amounts stored of a chemical precursor that may trigger the phenomenon.
Is it safe to eat garlic when it turns green?
The blue-green hue of garlic may be produced by heating it or combining it with an acid. LaBorde and López-Alt also point out that older garlic is more likely to change colours since it probably has more of the chemical precursors that might lead to the colour shift hidden away. Eating either blue or green garlic is completely safe.
Why is my garlic turning blue when I cook it?
If garlic is exposed for a prolonged period of time to any acidic element, such as vinegar or lemon juice, it may become blue or green. The molecules of the garlic cloves are reorganised by the acidity. This produces polypyrroles, chemicals that provide the green or blue colour to garlic cloves.
Why is my garlic turning green?
It is most likely due to the reaction of sulfur compounds with amino acids building blocks of protein in garlic. A green tint is produced in garlic when these compounds aided by enzymes react to form new molecules. However, the green color of garlic can also be due to the sprouting of roots at the core of the clove.