Is there Manuka Honey for Tea?

When Captain James Cook anchored in New Zealand after a long voyage across the Pacific Ocean he was probably dying for a cup-of-tea. It was already a popular drink in England by the 18th Century when he sailed from Whitby, and a pot of tea warming in a brown betty is still a familiar sight in Yorkshire. I remember people brewing it for hours to make a really strong cuppa, extracting enough tannin to cure a deer hide.

brew a cup of tea
my Brown Betty

The native people he encountered persuaded him to try making “tea” from the spiky leaves of a scraggy tree called Manuka in the Maori language, which his sailors named the tea tree (not to be confused with the Australian tea tree from which the famous oil is extracted). I too was missing Yorkshire tea on my latest visit to New Zealand and wanted to try Maori tea for myself. After brewing a bunch of dried tea tree leaves for an hour, the water turned faintly orange and developed a citrus fragrance. If appearances could be trusted, the “tea” was promising, but I hadn’t reckoned on a bitter assault of my palate by the terpenoids. Perhaps that experience hurried Cook home for his brown betty.

Tea tree (Manuka)
Tea tree (Manuka)

The tea tree might have remained in obscurity after Cook’s experiment because, apart from a seasonal show of white or pink blossoms, it is an ugly shrub. But sometimes there is great virtue and fortune hiding beneath an unattractive exterior. Someone noticed that nectar collected by honey bees from tea trees makes a highly distinctive kind of honey, which has become the most prized in the world. It looks like mud in a bottle or spread across a slice of toast, and most unappetizing compared to the clear and syrupy product in your grocery store. It tastes oily or earthy and lacks the intense sweetness that characterizes most honeys. It is so expensive that Tesco supermarkets in the UK lock it inside security boxes with alarms to thwart shoplifting. As caviar is to shrimp and vintage Burgundy is to a cheap Cab, manuka is to “garden” types of honey. It is gooey gold, as rare as the ore itself.

The reputation of Manuka honey forges past scientific and pecuniary caution like most other supposed health products, and goes even further. Some people speak of it reverently as if it is holy water. There is no doubt that it has antimicrobial activity, but regular honey has plenty from its peroxide and high sugar content from which it earned a reputation for wound healing even in ancient times. But it possesses other pharmacological properties that are unique and may make it superior for attacking bacteria and fungi. At least some medical professionals are convinced, because medical grade Manuka honey is used in wound dressings (it stings). But most people purchase it because they enjoy a spoonful as a treat, or to impress their guests with a luxury product going up in smoke after spreading it liberally over barbecued fish, or for treating a skin eruption or warding off a gastrointestinal devil. Manuka enjoys a high reputation because it is a product of the relatively clean New Zealand environment where it is harvested from hives deep in the bush far from crop spraying.

It is la crème de la crème for New Zealand beekeepers and their most valuable “crop” which they must guard against fake products because it is as vulnerable to fraud as a Vuitton or Gucci handbag.

Some cheaper Manuka honey mixes on NZ grocery shelves
Some cheaper Manuka honey mixes on NZ grocery shelves

As a natural product honey can never be guaranteed to be uniform or from a “pure” source. Bees have favorite food plants but a colony visits a range of flowers which vary during the flying season. Manuka is not in flower all the year round, and the properties of its nectar vary between seasons, sites and specimens. Every batch of honey is different, and therein is a dilemma for beekeepers preserving the quality and reputation of their product, and for customers who don’t want to be scammed.

Of course, you can be sure that honey marketed as Manuka at unbelievably cheap prices is unbelievable, but beyond that the customer has to look for an official sign of authenticity. There are plenty of brands labeled Manuka that honestly declare the fraction of the whole, but according to what I heard over 80% of that advertised as the genuine thing in Asia is adulterated with regular honey or syrup.

Beekeepers go to great lengths to protect their industry. One firm I know safeguards its product by bottling and labeling the entire harvest on its own premises. It is also licensed by the Unique Manuka Factor Honey Association which is a guarantor of quality after testing three compounds that account for some of the non-peroxide antimicrobial activity. Genuine products can be recognized by the UMF® label, and are rated for quality up to 20 (rarely available). UMF is the “official” standard, but customers are confused by ratings from an independent company which uses a different scale. In one airport shop I saw a kilogram bottle rated at MGO 800+ which is roughly equivalent to UMF 20. By the way, it cost NZ$800!

You might think the best test of Manuka in honey is the proportion of pollen grains from the tea tree. Unfortunately, the related Kanuka tree is also a favorite food plant of bees, but it has almost indistinguishable pollen and it doesn’t produce such a valuable crop of honey.

The UMF laboratory tests three compounds, including methylglyoxal (MGO) which is given the most credit for healing properties since it kills bacteria long after peroxide activity is degraded by catalase activity in human tissues. There little MGO in fresh honey, but it builds up during storage as the concentration of dihydroxyacetone (DHA) declines. DHA is the second compound tested for UMF. It is used elsewhere as a fake sun-tanning agent and I guess contributes to the browning of proteins in Manuka honey.

Beekeepers can’t sleep peacefully after their products pass the UMF test because MGO and DHA can be bought as pure compounds for adulterating “garden quality” honey. When I checked with an American chemical company from which I used to obtain lab supplies I could buy quantities of both compounds for a few hundred bucks, enough to fool labs of tons of honey. The industry is aware that a cat-and-mouse game may already be in play with fraudsters and is looking for more robust markers. Gas chromatography-mass spectrometry can generate a molecular fingerprint of honey samples which should be foolproof. The equipment tests far more markers than can easily be added and requires technical expertise, but the expense will eat into profits. The tea tree produces a wondrous honey, but it comes at a high cost and bitter taste.

Auckland Airport
Medicate with Manuka! (Auckland Int. Airport)

Posted in New Zealand

Next Post: Two Beekeepers in the New Zealand Bush

By Roger Gosden

A British and American scientist specializing in reproduction & embryology whose career spanned from Cambridge to Cornell's Weill Medical College in NYC. He married Lucinda Veeck, the embryologist for the first successful IVF team in America. They retired to Virginia, where he became a master naturalist and writer affiliated with William & Mary.

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