Citrus Peel (Or Chen Pi) as they are commonly known are a curious spice sold almost ubiquitously throughout China, particularly the South. They come from the skin of a mandarin (tangerine), so taste-wise they're very similar to lemon rind, except these ones dried... and aged. These Citrus Peels have been aged for 5 years in cool, dry, dark conditions to bring out the full flavour. Usually a minimum of 3 years is needed for good flavour, and at 5 years we find the best flavour is already present. Beyond 5 years, citrus peels get more and more expensive, with no discernable taste difference to us... possibly due to the large number of fakes! Citrus peels are actually known as one of the "3 treasures" in Guangdong Province, where it is almost exclusively used as in herbal medicine, not cooking! Chen Pi gets more expensive with age, as they get darker in colour, losing moisture. The aroma is extremely sharp, sweet, and taste is slightly bitter. We love using these for cooking "Tong Sui" - traditional sweet, warm soups and custards at the end of a Cantonese meal.