Mad about mushrooms

A peek at the magic that happens at a mushroom farm!

If you’re like me, chances are mushrooms became an acquired taste. When I first tasted them as a child, they’d come out of a tin and the texture just wasn’t appealing at all to me. Fast forward to my teen years (about the same time I discovered my parents had been deceiving me and hamburgers were not, in fact, more delicious than steak) and I began to become a much more adventuresome eater. One of my new favourite ingredients was mushrooms. I loved them for the rich, earthy flavour – often described as umami – they add to soups, stews, omelettes, stir fries, pizzas and more (check the bottom of this post for a few of my favourite recipes). On a recent tour of several Ottawa-area farms, organized by Farm and Food Care Ontario, one of our stops was Carleton Mushroom Farms in Osgoode. I learned so much about mushrooms from our host at the farm (more about that in a moment) as well as from Marianne Muth of Mushrooms Canada who was along for the ride.

I was pleasantly surprised to learn that almost all the fresh mushrooms available in Canadian grocery stores are Canadian grown and cultivated year round. There are almost 200 commercial mushroom farms across the country; mostly in Ontario and British Columbia. Combined, they grow over 200 million pounds (91,000 tonnes) of mushrooms annually, all of which are picked by hand! Canada exports 40% of its fresh mushrooms (or 80 million pounds) – mostly to the United States and Japan – and imports 45 million pounds of canned or processed mushrooms, mostly from China. Annual per capita consumption of fresh mushrooms in Canada is approximately 3.5 pounds (1.6 kg).

It likely won’t surprise you to learn that the most popular mushroom in Canada is the white button, followed by brown (cremini) and portabella (which are actually just large cremini mushrooms). Specialty mushrooms, such as shiitake, oyster, king oyster, and enoki are gaining in popularity and all are cultivated here.

I enjoy mushrooms because of their taste but am happy to now know that a half-cup serving of cooked, sliced mushrooms has 1 gram of fibre and is a source of phosphorus, potassium, copper, selenium, niacin and pantothenic acid, in addition to having just 14 calories and virtually no fat. Mushrooms are also a good source of riboflavin, and are the only vegetable in the produce section with natural Vitamin D – and if you put raw mushrooms in a sunny windowsill, uncovered, they’ll actually absorb more Vitamin D!

As mentioned, our group was fortunate to visit a large Ottawa-area producer, Carleton Mushroom Farms. Now a second generation family operation, it was founded in 1984 by Fernando and Anabela Medeiros and has tripled in size over the years. Today, sons Fernando Jr. and Mike run the operation and have implemented numerous improvements to increase efficiency and yields.

As an example, the Medeiros family used to make their own compost (the medium in which cultivated mushrooms grow) outdoors then bring it indoors where it would be sterilized for one week. Today, they are partners in a shared facility that make 1000 tons of compost a week for a number of Ontario mushrooms farms; it is a process that takes two weeks and includes adding peat blended with sugar beet lime and water to bring up the pH level in the compost-based growing medium which is known as substrate.

The growing process begins with mycelium (actively growing mushroom culture) being propagated in a lab on sterilized grains of millet or rye; these inoculated grains are referred to as spawn and Carleton buys its spawn from a central supplier. The spawn is planted in the nutrient-rich, compost-based substrate. White strands appear on the surface of the substrate after about 5 days; this is the mycelium, the living fungus that produces the mushrooms. By about day 11 the mushrooms are visible; they are called ‘pins’ at this first stage of growth and from this point on, they double in size every 24 hours! Picking starts at about day 30 and continues for two weeks.

During our tour we learned about their scrupulous attention to hygiene in every aspect of the operation. In addition, we saw how each growing room is climate controlled ever so precisely via a computerized system that monitors water levels, carbon dioxide and temperature. The rooms are earthy smelling without being stinky, humid without being oppressive and scrupulously clean. As we moved from one growing stage to the next through subsequent rooms, it was genuinely exciting to see the progress from mycelia to pins to ready-for-harvest mushrooms.

As mentioned, all harvesting is done by hand and pickers get paid by weight. The more skilled the picker, the greater their yield as they learn how to stagger their picking over 3 to 5 days to give the smaller mushrooms time to develop, thereby allowing them to harvest more from their allotted sections in the growing rooms. White mushrooms yield about 5.5 – 6.5 pounds per square foot while brown mushrooms yield about a pound less which is why they cost more. There will be several pickings over about a two week period as the mushroom pins continue to develop and then the spent compost is removed (to be mixed with topsoil by local processors who resell it as a garden enricher) and the process begins all over again.

Currently, Carleton Mushrooms harvest almost 8 million pounds annually and they are in the process of building a number of additional grow rooms to increase their capacity as mushrooms continue to gain in popularity. On the very rare weeks that the farm finds itself with any surplus, unsold mushrooms, these are donated to food banks in Ottawa and Montreal.

So just how fresh are the mushrooms we buy in our local grocery stores? In the Ottawa area, they’ve usually been picked just a day or two before arriving in stores. And yes, experts confirm what you’ve been told; refrigerated in a paper bag is the best way to store mushrooms and there’s no need to wash before eating or cooking, just brush off as needed.

I love cooking with and eating mushrooms; here are a few of my favourite creations that incorporate them:

Vegetarian Lasagna with mushrooms, leeks and kale

Vegan Shepherd’s Pie in Portobello Mushroom Caps 

Slow Cooker Beef, Mushroom and Barley Stew

Thanks to Farm and Food Care Ontario for making this thoroughly educational and enjoyable tour possible.