The biology behind prized, expensive truffles (2024)

From truffle sex to truffles in Harvard Yard, here's everything you'll ever need to know about the prized fungi.

With truffle season in full swing, chefs and servers are busy slicing slices of mushroom gold onto dishes all over the city. To better appreciate your next taste of these earthly delights, here's what you need to know about the science behind growing and eating truffles.

What exactly is a truffle and what is its relationship with a mushroom?

Truffles are underground mushrooms. When fungi have 'sex' and spread their offspring (spores), they normally do so in the open air. The brightly colored mushrooms in the forest that look like thiscapsofcupsare typical mushrooms that come from the ground. These mushrooms are coated with spores that spread, land in a new location and grow into a new mushroom.

However, truffles prefer to have sex in the dark. Thatgillswhich leave the spores of a typical mushroom, packed together in truffles to form a pouch. It is these upside-down mushroom pockets that truffle hunting dogs find buried in the ground. When you eat a piece of truffle, you are eating millions of tiny spores that would have grown into baby truffles.

Each bite of truffle is filled with thousands of microscopic spores. This summer truffle has been cut in half to reveal a light interior where thousands of tiny pockets of microscopic spores (inset) can be found.

Why are truffles so rare and expensive?

Truffles are rare because they only grow under very specific conditions. Unlike other fungi that grow on dead tree trunks or in the soil (see ourEarlier messagesabout the three ways nature makes a mushroom), truffles need a living plant to grow in a so-called relationshipectomycorrhiza-symbiose. The truffles extract sugar from the roots of the tree and in return the truffles provide nutrients from the soil to their tree partner. Truffles only grow on certain types of trees, including oak, hazel, poplar, beech and pine.

The challenge of growing significant quantities of truffles is that you have to grow both the tree and the fungus – and they have to work together, while a whole zoo of other microbes lurk in the ground. Scientists still don't know all the conditions that trigger the fungus to create a truffle structure, so it's impossible to force truffles to grow. Growing the right trees in the right soil type and climate is the best thing you can do; the rest is largely up to nature.

Most truffles are still harvested in Europe, where they have been growing for millions of years. What has beenconsiderable successgrowing high quality truffles in Australia andchecks the successgrow them in the US.

What are the main types of truffles?

White truffles (A huge tuber)

The most prized, most aromatic and most expensive truffles are the white truffles. Their season extends fromNovember to early January. Prices are usually in the region of several thousand dollars per pound. This year's white truffle season is one of the best in a long time: it started early, prices are low (relatively speaking) and quality is high. If you've never had them, 'tis the season to try them.

A trio of white truffles from this season in No. 9 Park.

Black Truffles (Knolmelanosporum)

Black truffles are a bit woodier and spongier than white truffles, and not as aromatic. But these have a fantastic truffle flavor and are available fromDecember to Marchwhen they come from France as Périgord truffles. In the summer we get them from Australia. Depending on the season, black truffles are usually half the price of white truffles.

A cross section of a black Périgord truffle.

Summer truffles (Summer tuber)

Just like their cousins ​​the black truffles, summer truffles and Burgundian truffles (Tuber hook) are black on the outside. However, their interiors are much lighter in color, ranging from light brown to white. These truffles usually have minimal truffle flavor and instead have a simple mushroom earthiness. They are the cheapest of all truffles (about a tenth of the price of white truffles) and are available in the summer, when they come from Italy and France. These truffles are beautiful and delicious, but because of their simple taste they often leave people wondering about the truffle hype.

A cross section of a summer truffle.

Other truffles

The three types of truffles described above are the main types of truffles used in restaurants around the world. But there are hundreds of varieties of truffles around the world, and some of these lesser-known truffles may one day break onto the culinary scene.

Numerous speciesdesert trufflesgrow in arid areas in Europe, Africa and Asia, and have done soplayed important rolesin the cultures of many desert communities. American pecan farmers have gotten some helpAmerican truffle researchersto explore the ecology and culinary potential of the pecan truffle (Knol Lyonii). Truffles can even be found in our own backyards, although it is highly unlikely that it is a species that would taste good. During his Ph.D. research, Benfound trufflesunder an oak tree in Harvard Yard.

Which chemicals are responsible for giving truffles their special taste?

There are many volatile compounds that researchers have identified in truffles that contribute to their aromas. Each strain has a different set of chemicals that provide unique aroma profiles. INa study of the white truffle37 different compounds were found associated with the typical white truffle aroma.

There is one compound that is believed to be common to all truffle speciesdimethylsulfide. This is a volatile sulfur compound often associated with rotten cabbage flavors in ripe cheeses. This same mixture gives truffles their funky, earthy notes. Interestingly, dimethyl sulfide also makes an important contributionthe smell of farts.

What is the best way to use a truffle in a dish?

Scott likes to combine the white truffle with a Parmigiano-Reggiano risotto or perfect scrambled eggs. He also likes white truffles, shaved over handmade tagliatelle with lots of butter and Parmesan cheese. If you use truffles with paste, make sure the paste is hot to bring out the mushroom's volatiles.

Combine black truffles with beef. More specifically, we love it with a roasted ribeye, topped with a slice of seared foie gras and a Madeira pan sauce. Black truffle also goes well with surf and turf.

For summer truffle, you can use shaving on anything you want to impress someone. Scott tends to use a dish with stock so that the limited truffle flavor is spread out and becomes a little more dominant. Braised lamb shoulder with salsa verde and bagna cauda, ​​for example? Shave some summer truffle on it.

Why are European truffles becoming increasingly difficult to obtain?

European truffle harvesters have noticed a steady decline in truffle abundance in recent decades. Scientists believe climate change may be partly to blame.Summers are becoming drierIn many regions where truffles are grown, these dry summers inhibit the growth of truffle mushrooms. This could even be a good thing for other parts of the world where climate change is creating new environments where truffles can be grown.

Another threat to the future of European truffles is the Chinese truffles that are invading European truffle plots. It is unclear how they got there, but a type of truffle from China (An indicator tuber) have been found in Italian truffle grounds. French truffle researchersshocked in a newspaperpublished in 2008 when this discovery was made, as these truffles are believed to be more aggressive than the native truffles and could replace these highly prized species. The French believe that Chinese truffles have much less flavor than their European counterparts. Chinese truffles are sometimes laced with a synthetic truffle flavor and sold as fraudulent versions of their European truffle counterparts. Unlike a dandelion, weed fungi are difficult to control because they spend most of their time underground. Europeans therefore have few options to protect their truffle heritage. Check this outgreat 60 minute reportfor more information about the threats to the European truffle market.