Brussels Sprouts

Brassica oleracea var. gemmifera

Brussels sprouts are small, dense cabbage buds that grow along a tall stalk. Their flavor is more assertive and nuttier than head cabbage.¹

They are close relatives of cabbage, kale, broccoli, and cauliflower—all different cultivated forms of Brassica oleracea. Like those vegetables, they contain glucosinolates, sulfur-rich compounds involved in brassica defense chemistry.²

The individual sprouts are axillary buds: compact heads that form where leaves meet the main stalk. They tolerate several moderate freezes in Maine.³

In the Northeast, Brussels sprouts are treated as a fall crop rather than a quick summer vegetable. Maine’s planting guidance starts them as transplants for a late-season harvest, and Extension notes that several moderate freezes generally improve their quality.³⁴ Cold weather slows the plant while leaving the buds on the stalk, giving the region’s long autumn a useful role in the ingredient’s flavor.

Each sprout is a compressed lateral bud, not a miniature fruit or a separate root. The stalk keeps producing these buds upward as the lower ones mature, which is why the harvest has a built-in progression from large outer sprouts to tighter younger ones. Their sulfur chemistry is part of the same defense system found throughout Brassica oleracea, but the cool-grown texture and compact leaves give Brussels sprouts a distinct eating character.²⁵

Glucosinolate chemistry is not evenly distributed through a sprout. The young center has especially active flavor-forming enzymes and high concentrations of flavor precursors, which helps explain why the core can taste stronger and more bitter than the outer leaves. Heat first accelerates the enzyme reaction, then stops it; prolonged cooking instead drives the sulfur compounds toward the persistent aroma associated with overcooked cabbage.⁵