Ask Chef Mary: Why does fennel turn brown?


Dear Chef Mary,

I was recently at the grocery store and saw that fennel is in season in my area (Northern California). I am always intrigued with fennel but I never know what to do with it and when I do use it, it typically turns brown.

What is it?

What do I do with it?

(c) HMFG copyright photo by mary moran

(c) HMFG copyright photo by mary moran

Why does it turn brown?

How do I prevent it from turning brown?

And why should I eat it?

Sincerely, Sue

Dear Sue,

I’m sure you know, but for those who don’t, the fennel is composed of a white or light green bulb, superimposed stalks, feathery leaves and crunchy seeds, all of which are edible and nutritious. It’s a sweet, light and liquorish flavored vegetable that has a lot to offer.

I love to add fennel to chicken or fish dishes or even to salads to give it an extra layer of flavor that will surely confuse your guests. You can also braise fennel with white wine and serve it as a side. The key to fennel is to cook it through or serve it completely raw, and if it’s raw slice it really thin and serve with a citrus dressing.

Fennel, like apples, turns brown because of oxidation. Similar to apples, the best way to prevent oxidation is by completely submerging the fennel in a solution made up of 3 parts water and 1 part acid. Serve or cook it the same day you cut it. Fennel does not keep otherwise.

You should eat fennel because it’s filled with vitamin C and B for a better immune system, it has fiber for lowering cholesterol and risk of colon cancer and potassium for lowering blood pressure.


Sue, fennel is just now coming into season and is most prevalent in Northern California, which is why you are seeing it on your grocery store shelves. Fennel is delicious and I highly recommend adding it to your monthly menu. Keep cooking simple to get a great outcome and remember that good olive oil, white wine and lemon are perfect companions to this sweet and delicious vegetable.

Good Luck!

Chef Mary


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