Why Does My Cabbage Taste Bitter or Too Strong?

Garden cabbages that taste harshly bitter or have an unpleasantly strong, sulphurous flavour are disappointing when you expected the mild, sweet taste that makes fresh garden cabbage so worthwhile. Cabbage flavour is strongly influenced by the growing conditions and the timing of harvest — cool-grown autumn and winter cabbages are typically the sweetest and most flavourful, while hot-summer cabbages can be harsh and strong. Understanding what creates bitter flavour helps you choose the right variety and harvest at the right time.

Heat stress and bitterness

Brassicas grown through hot summer conditions accumulate glucosinolates (the sulphur-containing compounds responsible for the brassica family's characteristic flavour) at higher concentrations when under heat stress. A cabbage that forms its head in July and August heat tends to taste stronger and more bitter than one maturing in October. This is partly why summer cabbages are not regarded as the finest for raw eating or gentle cooking — they are more suited to robust preparations. If bitter summer flavour is a recurring problem, grow autumn and winter varieties for fresh eating quality.

Outer leaves versus inner head

The outer, dark-green leaves of any cabbage are more bitter and strongly flavoured than the pale inner head leaves. If you are tasting the outer leaves, the strong flavour is to be expected and is characteristic of most fresh brassicas. The inner leaves — particularly in a well-formed head — are mild, sweet, and much less bitter. Discard the outer layer of leaves, which are also tougher and coarser in texture, and use only the inner head for fresh eating or delicate preparations.

Frost and flavour improvement

A hard frost converts some of the starches in cabbage tissue to sugars, measurably sweetening the flavour. Autumn and winter cabbages allowed to stand through the first frosts of the season consistently taste better than the same variety harvested before any frost. Savoy varieties benefit the most dramatically from frost exposure. If your growing season allows, leaving autumn cabbages to stand until after the first frost of November substantially improves their eating quality.