Beech

Wood fungi want sterilised sawdust, not pasteurised, and a white block is not yet a block you cut.

Why wood is not pasteurised

Beech is food for fungi that know how to take apart lignin and cellulose. Shiitake, lion’s mane, reishi, and oyster too if you decide to give it a dense block instead of straw. It is poorer in simple sugars than grain, slower to colonise, and it holds a shape. That shape is why, once taken, it can fruit for several flushes without collapsing the way a stalk does. It is also why a mistake at the start stays in the block: sawdust does not “rinse out”.

Pasteurisation, the step that on straw lowers the competitors and lets an aggressive oyster win, is not enough on wood. Wood mycelium is often slower. The survivors of a bath at 70 °C have time. If the wood is supplemented as well, that time becomes a Trichoderma victory. Sterilisation — saturated steam around 121 °C, held until the core of the bag gets there too — is the right contract. A wood “pasteurised to be safe” is an imaginary safety. You have selected the organisms that resist moderate heat and you have left them a food your fungus will not occupy for weeks.

Sterilised beech is beech sawdust or fibre already through that steam, in one or two kilos. It is not a raw pellet. It should not be reconstituted and it should not be reboiled in an open pot, which does not reach the temperature and wets the filter. You spawn it with colonised grain. A syringe alone, a few millilitres in a kilo of wood, is a point in a desert: it can work in a bag with a port designed for the grain, and it often loses in a block of sawdust alone that is opened or stabbed once.

Substrato Funghi Faggio Sterilizzato — 1 kg / 2 kg€12,90

Beech alone, or beech enriched

Beech on its own is the sober substrate. Less nitrogen, a slower run, less of a banquet for a mould if a spore gets in at the moment you mix the spawn. The fruits, when they come, come on a block that has had time to consolidate. It is not “less serious” than the enriched mix. It is the choice in which a hygiene mistake has a little less to eat.

Master mix is the other choice. It is hardwood sawdust plus a nitrogen supplement, generally soy hulls, sometimes bran. The supplement gives the mycelium amino acids that are scarce in sawdust alone. The colony closes sooner. The same supplement is excellent food for competitors, if sterilisation of the core was not complete or if you hold the bag open while you look for the spoon. It is not a lever of guaranteed kilos. It is a trade: speed against a narrower margin of error. A master mix pasteurised instead of sterilised is the trade done badly. You have the richness and you lack the starting void.

Sterilised master mix is that block already closed by the steam. You treat it as a rich food: spawn well distributed, a short opening, no “check” halfway. If it smells sour before it is white, you do not save it by removing the supplement afterwards. The supplement is already in the volume. You discard it closed.

Substrato Funghi Master Mix Sterilizzato — 1 kg / 2 kg€14,90

The choice between the two is not a moral one. A first shiitake can sit on beech alone, so you learn browning without also having a nervous substrate. A lion’s mane you want to see close the block on a more readable clock can sit on master mix, if the sterilisation really is that and your hands are brief. Oyster on beech works in both cases and often does not need it: straw is enough. You put it on wood when you want a block that lasts and can be handled, not because straw is forbidden to it.

How much spawn, and how it enters

One part colonised grain to five or ten parts wood, by volume, is the usual window. By weight, moist wood is denser than straw, so looking only at kilos can mislead: a kilo of compact sawdust is less volume than a kilo of airy straw. The seeds have to disappear into the wood, not stay in a layer. A few seeds in a large bag leave the core bare for a month. That core, on a master mix, is the place where a single spore becomes a colony while you wait for the white on the wall.

You open the minimum. Clean bench, washed hands, alcohol, no plants, no fan. You crumble the spawn, you mix, you close it again with the filter clear. Every minute open is a minute in which sterile wood, especially if supplemented, meets the kitchen. It is not the moment to answer the phone with the gloves you do not have. If the block arrives with grain and wood already in the same bag, the path is the other one: you colonise the rye through the port first, then you mix from the outside. You do not open both methods on the same bag “to go faster”.

Wood that is too wet drips and heads toward a core without air. Proper wood, squeezed, gives a few drops. Dry wood is pale, crumbly, and the mycelium makes a veil on it that does not become a block. You do not wet it afterwards, with a syringe or with a spray into an open bag. Water added late does not distribute and creates the puddle bacteria use. You start from the block that is already right, or you do not start.

White does not mean cutting

Colonisation finishes when the block is one body, white through, not when the plastic has hazed over. A dark core is wood not taken. Cutting it is opening a larder. On a master mix the larder is rich, and green sits down in it within a few days. You wait. You turn the bag. You smell the filter: fresh mushroom, not sour.

Shiitake, even as a white block, is not cut. It has to brown. The surface turns brown, sometimes knobbly, and makes a crust. That is maturation, not mould. It can take weeks inside the closed bag. The crust is how the block holds water and then produces. A cut on the day of the white interrupts that skin. You get a block that dries or that moulds on the wound, and a wrong conclusion about the species. When the brown is widespread and the block is firm, then you take the plastic off or open a window, often after a cooler rest, with humidity and exchange. Single dates do not travel from one room to another.

Lion’s mane does not make this crust. When the block is consolidated you open a small cut, and the humidity on the wound has to be high, without a direct jet on the pins. The fruits dry and yellow with little water in the air, and they deform with too much CO2, a little like the long stems of an oyster but with a shape people mistake for “the fungus just looks like that”. A bit of coral comes from still air. A more defined fruit comes from exchange, without drying it out.

Reishi is slower than either. In still air and high CO2 it makes antlers. With more exchange it spreads a cap. That is not a disease of the block. It is the same species reading the gas. Cutting it halfway through colonisation does not speed the choice: it contaminates the wood. Oyster on beech is cut as on straw, a side slit on a white, firm block, and it forgives a tight calendar more than the others do. That is not a reason to use its clock for the shiitake sitting in the same kind of bag.

Raw pellets want an autoclave

Beech pellets are compressed wood, dry, not sterile. They swell with water. The final volume is much larger than the pellet, and it has to be calculated before you fill a bag, otherwise the swell opens the seal or leaves you a brick with no useful filter. The right hydration is that of the finished block: moist, a few drops if you squeeze a handful, no lake at the bottom. Then you need steam under pressure. Not a bucket of hot water. Not an hour of boiling. Pasteurising pellets, for shiitake or lion’s mane or reishi, is the straw method applied to the wrong food.

Beech pellets are the ingredient if you are the one running the autoclave. They should be wood, not a stove pellet with glues, paints or softwood resins if the species wants hardwood. The word beech on a substrate pack is the starting point. It is not the sterilisation. You do that afterwards, in a filter bag, with a cap or a seal that can take the cycle.

Pellet di Faggio per Substrato Funghi — 1 kg / 2 kg / 5 kg€6,00

The core is the last part to reach temperature. A bottle of agar gets there in a quarter of an hour because it is small and liquid. A bag of sawdust of one or two kilos is dense, it insulates the centre, and it often asks for a couple of hours at 121 °C once the cooker is at pressure, not twenty minutes copied from a plate. The exact number depends on the shape of the bag and the cooker. The principle does not: if the centre does not get there, the centre is not sterile, and mould starts from inside when the mycelium is still halfway. You usually do not have a thermometer in the core. That is why the long times exist, and why a bag that is already sterilised is the coherent choice if your cooker does not hold pressure or cannot fit a volume of that kind. Failing the cycle and calling it “clean wood” is the slowest way to lose a shiitake.

After the cycle you let the pressure fall on its own. You let it cool completely. You inoculate or spawn only at room temperature. Hot wood kills spawn even if the spawn is beautiful and white. A pellet forgotten halfway through hydration, neither dry nor ready, ferments in the bucket. That does not get sterilised “anyway” in the hope that steam will sort out the acid. You start again from dry pellet.

A block a month, if you do not have the steam

Anyone who does not sterilise at home depends on the age of the block that arrives. Sterilised wood does not stay empty forever. The filter exchanges, the edges can dry, a rare survivor has months to show itself. A block spawned near arrival is the object the cycle was describing. A pile in the cellar from a whole season is a bet on the filter.

The Hardwood Club is a two-kilo sterilised beech block that arrives each month. The point is to line the arrival up with the moment you have spawn ready, not to pile up wood that ages while the grain colonises. It does not change how you spawn. It changes how many days the steam has behind it. If this month’s block waits in a cool place, in the dark, for a couple of weeks, it is still inside the reasoning. If it waits for autumn in a very hot cupboard, the name of the club does not repair it.

The spawn you sow it with has to be finished grain, white, not a bag you broke yesterday that still has bare seeds. Sterilised wood is undefended. Bare seeds are unoccupied food you put inside it yourself. It is the opposite of the gesture.

What gets discarded without opening

Green, even a streak, in a master mix: lost. The supplement will do the rest if you open it. You bag it closed. A sharp smell, wood dark and slimy in the core visible from outside: lost, often too much water or a sterilisation cycle the centre never saw. A thin white that never consolidates, on a light block: wood too dry, not a “slow” species. You recognise it and you do not cut it to see whether it fruits anyway. A shiitake browning, even, with a mushroom smell: you do not discard it. You wait for the crust.

Black or green moulds are judged closed. Photographing an open bag on the table is sowing the kitchen where you will inoculate tomorrow. Beech is good food for them too. The difference between your fungus and theirs, at the start, is only who got in first and at how many points.

What this guide is not

It is not permission to pasteurise sawdust as if it were straw, and it is not a date on which the block “should” be ready. It is sterilised lignin, spawned with real grain, left to become a whole body before any cut. Shiitake, after that body, still wants a skin. Pellets, if they start from dry, still want the steam. The rest is patience measured on the smell and on the core of the block, not on the colour of the plastic.