Ginger left in the ground past the frosts does not get sweeter. It goes woody. The rhizome hardens, the fibers coarsen until they catch in the teeth, and the heat — which in a young pink-shouldered piece is bright and almost fruity — turns dense and slow and stays at the back of the throat long after the dish is finished. Cooks buy the young stuff for fragrance. They buy the old stuff when they want something in the pot to bite.
The agronomist Wang Zhen wrote it down in the Yuan dynasty: ginger past the White Dew season becomes lǎo jiāng, old ginger, fibrous, and the taste extremely pungent — the older it gets, the hotter it gets.
What it actually means
Jiāng háishì lǎo de là. Of ginger, it is still the old one that is hot.
The usual English rendering is “the older the ginger, the spicier,” and the usual use is a compliment: the veteran outmaneuvered the newcomer, the retired manager spotted the flaw nobody else did, the grandmother won the argument. In that register it belongs to the international family of sayings about experience.
But look at what the sentence actually claims. Not that old ginger knows more. Not that it has seen more seasons or accumulated more merit. That it is hotter — that the quality which makes ginger difficult has concentrated rather than faded. The proverb is not about wisdom. It is about potency, and specifically about the kind of potency that stings the person on the receiving end.
Where it comes from
The figure has a documented ancestor, and the ancestor is not a compliment paid to anyone. It is a refusal.
In 1138 the Jin sent envoys to the Southern Song court with a demand that the Song receive their emperor’s edict — a humiliation of the first order, and one that Qin Hui, the chancellor steering the court toward accommodation, was prepared to accept. Yan Dunfu, a senior official and a great-grandson of the poet Yan Shu, submitted a memorial opposing it. Qin Hui then did the ordinary thing and sent someone to Yan privately, with the offer of high office attached.
The History of Song records what Yan said to the intermediary: 「吾終不為身計誤國家，況吾薑桂之性，到老愈辣，請勿言。」 I will not in the end harm the state for my own sake; besides, my nature is that of ginger and cinnamon — the older it gets, the hotter it burns. Say no more.
Jiāng guì zhī xìng — the nature of ginger and cinnamon — became a set phrase for a character that grows more unbending with age. And the thing being described in the original is not shrewdness at all. It is the quality of being harder to buy. Yan is not telling the man that he is too clever to be tricked. He is telling him that he has become, over a long career, more difficult, less pliable, worse to negotiate with. The heat is aimed at the person holding the bribe.
Somewhere between the twelfth century and the modern proverb, the saying drifted from incorruptibility to competence. That is a real loss, and it is the sort of thing that happens to a figure of speech when it gets popular: the edge that made it worth saying wears down into a general compliment about seniority.
How it gets used today
The modern lexical glosses put it plainly — the phrase describes an older person as experienced, wide in knowledge, and practiced in handling affairs. That is the sense in which a Chinese dictionary will define it and the sense in which most speakers will use it.
It is worth noting that the compliment retains a small amount of the original heat. To say of someone that they are the old ginger is to concede that they got the better of somebody, which is not quite the same as praising their character.
Cousins from other tongues
Japanese makes the same comparison and does it as a pun. Kame no kō yori toshi no kō — 亀の甲より年の功 — rather than the turtle’s shell, the merit of years. The two kō are different characters that sound identical, one meaning shell and the other meaning merit or accomplishment, and the sentence turns on that echo. What it sets against age is a natural endowment: the turtle has armor and famous longevity and did nothing to earn either. Years of kō are earned. Where the Chinese says age concentrates something already present, the Japanese says age adds something, and the difference is between distillation and accumulation.
Spanish arrives at it through a joke about the devil. Más sabe el diablo por viejo que por diablo — the devil knows more from being old than from being a devil. This is the wittiest of the group and quietly the most deflating: it takes the most formidable intelligence available in the Christian imagination and attributes his advantage to length of service. Whatever supernatural equipment he came with is worth less than the centuries of watching people. The Chinese proverb intensifies a substance; the Spanish one demotes a demon to a long-serving employee.
Mongolian moves the claim off people entirely. Khuuchin tsagaan esgii shine khar esgiigees deer — old white felt is better than new black felt. Felt is made, used, weathered, and either holds or does not; what recommends the old piece is that it has already survived the winters the new one has not been through. This is age as evidence rather than as heat or wit, and it belongs to a world where a mistake about which material to trust is a mistake about whether the tent stays up.
Why it matters
Set the four together and the Chinese one is the odd member. The others are all, in the end, about knowledge — merit accumulated, information gathered, reliability demonstrated. The ginger knows nothing. It has simply been in the ground long enough that the compound which makes it hot has concentrated, and the effect on anyone who bites into it is not instruction. It is a burn.
That is what Yan Dunfu meant when a man came to his house with an offer, and it survives faintly in the compliment the phrase has become: the old one is not merely wiser than you. The old one is harder to swallow.