Sprouts didn’t ask to be a controversial vegetable. If anything, they should appeal to our most traditional roast dinner instincts; tiny, leafy cabbages, with cauliflower-like stems and plenty of surface area to sop up gravy.
But somehow, the veggies divide us. And I do kind of get it ― they can run a little soggy if overcooked, they have a distinct, almost asparagus-like bitterness to them, and crucially, well, they don’t half stink sometimes.
If (like me) you thought that The Smell was just a common by-product of cooking the veg, though, you’d be wrong. The BBC points out that it’s all about timing ― “The one rule that holds true for cooking sprouts on the hob is that you should try to avoid cooking them for more than 5 minutes or the sulphurous compounds (isothiocyanates) within them will start to break down – and they will smell,” they say.
In fact, “The longer you cook them, the stronger the smell will get.”
So, we thought we’d look into how this pungent magic works ― and what you can do to fix it.
Iso-what now?
Isothiocyanates, the sulphurous compounds we mentioned above, are part of the defence system of brassicas (the family of veggies to which cabbages, broccoli, cauliflower, and more belong).
They taste bitter and are known to produce different smells in different plants.
“In cooked cauliflower, allyl isothiocyanate was found to be a key odourant, contributing pungent, black mustard-like notes,” Science Direct says, while “In salad rocket... two isothiocyanates and a thionitrile were noted to be abundant odour-active compounds.”
So, the flavours and smells run differently according to plants. And in Brussels sprouts, that damp, sulphoruous smell we associate with cabbage is on the molecular menu.
Cooking sprouts causes them to release an enzyme called myrosinase, which breaks down these compounds. So, as the BBC said, the longer they cook, the worse they stink.
So how long should I cook them for?
Healthline puts it at five to seven minutes if steaming, sautéing, or boiling sprouts, extending to 20–30 minutes if roasting them.
They add that cooking the veggies at above 140˚C can destroy a health-boosting compound in sprouts called glucosinolates, sharing that steaming or boiling sprouts helped them to retain the most nutrients in studies.
With that said, vitamins E and K increase when you cook cruciferous veggies ― so whatever method makes eating your veg the most palatable to you is probably the best one.
Just so long as you don’t stink up the kitchen while doing it, right?