The Secret Life of Supermarket Bread: Why Does It Stay Soft for Days?

Key points

• Bread goes stale mainly because starch molecules reorganise as the loaf cools and ages, not simply because it dries out. Supermarket sandwich loaves use emulsifiers, enzymes and packaging to slow this process and keep the crumb soft.
• Preservatives such as calcium propionate mainly inhibit mould, a separate problem from staling. Refrigeration can speed firming, while freezing preserves bread well.
• Nutrition depends on fibre, wholegrain content and sodium rather than ingredient count alone.