Your Winter Rhubarb Was Grown in the Dark (and Harvested by Candlelight!)

February 10, 2016

“Do you know how that’s grown? YouTube 'rhubarb picked by candlelight.'

This tip was given to me by a fellow Eataly patron. She was prompted into conversation, no doubt, by the small farm’s worth of rhubarb I was buying. We do a lot of recipe testing at Food52, which can involve sourcing some out-of-season ingredients. This proves particularly challenging in January and February, when “in-season” options are pretty limited here in New York.

So when I finally tracked down rhubarb, the magenta stalks hard to miss in a sea of dark green brassicas, I bought a conspicuous amount. And then I YouTubed.

The rhubarb available in the dead of winter is, indeed, harvested by candlelight. Called “forced rhubarb,” it’s grown in sheds or hothouses at a warm temperature under a thin layer of soil. The aim is to starve the rhubarb of light, preventing photosynthesis from occurring. This means that the rhubarb crowns must turn to their own energy stores to kick out stalks, which struggle upwards in search of light. The leaves, robbed of chlorophyll-producing light, are yellow instead of green, and the stalks, similarly chlorophyll-free, are red all the way through.

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If you stand outside one of these sheds, it’s possible to hear a faint popping and squeaking sound. That’s the rhubarb — it grows so rapidly the process is audible. “Our stalks are four inches today,” Tim Richter, a fourth-generation farmer at EG Richter Family Farms in Puyallup, Washington, told me over the phone. “Tomorrow they’ll be eight inches.”

Tim says his family has been forcing rhubarb since the 1940s, possibly even earlier. Tim and his crew plant rhubarb crowns in the fields outside for two summers, nurturing them to the point that, when they’re picked from the ground the following autumn, they’re bigger than a basketball and weigh roughly 100 pounds. Tim’s crowns spend about a month in a 55º hothouse designed specifically for rhubarb. They root down into the shallow dirt floor, and are ready to be picked starting in January. They’re picked three times a week until early April, when, conveniently, the field variety starts to come up.

Patrick Ahern, who goes by “Produce Pat,” is the resident rhubarb expert at Baldor Specialty Foods, Eataly’s produce supplier. He told me that the chief purpose of forcing rhubarb is to extend the growing season. Traditionally, rhubarb is a spring product, with a ten-week burst in April and a similar spurt around June or July. But forcing changes the rules of the game. “You can have rhubarb all year round now,” Pat said. Baldor supplies all of Eataly’s produce, and apparently the rhubarb I purchased was, in fact, forced.

Eataly’s current forced rhubarb stock is from Holland. It’s the U.K., however, that has the oldest claim on the practice: It was discovered in Chelsea, in London, in 1817. According to the Yorkshire Rhubarb Triangle Growers (a real organization), Yorkshire was the first place in the world to create sheds especially for the purpose of forcing, and Yorkshire farms have been the country’s chief forced rhubarb producers for over a century. The “Rhubarb Triangle” consists of Leeds, Wakefield, and Bradford —three cities in the county of Yorkshire that boast optimal growing conditions. The soil is nitrogen-rich, and the weather cold and wet, which suits the Siberian-native rhubarb plant perfectly. Until the start of World War II, a nightly 'Rhubarb Express' train from Yorkshire delivered 200 tons of stalks to London markets, so prized and so profitable was the Yorkshire variety.

In terms of flavor, Pat says the forced rhubarb is sweeter, redder, and more tender than the hardier, outdoor variety. Ex-Californian Claire Ptak, owner of London’s Violet Bakery, noticed a difference, too:

Beautiful forced rhubarb from Yorkshire seemed to be a real source of pride here in England. Indeed, this tall, thin, tender variety tasted worlds apart from the hefty, fibrous stalks I had tried to cook with one summer in Wyoming, when the only thing to do was to add strawberries to it and bake it into a pie.

While quick to insist that field rhubarb had its own merits, Tim concurred, describing forced rhubarb as a “delicacy”:

The difference between hothouse and field rhubarb is apples and oranges. Hothouse rhubarb is a delicacy. It’s filet mignon versus a chuck steak. The color inside [a hothouse rhubarb] is red, there’s no strings, it’s just flesh, versus the field rhubarb has got some chlorophyll in the stalk and it’s quite stringy.

So given the extended growing season and the quality of the product, why don’t more U.S. farms force rhubarb? Pat, who referred me to Tim, said he couldn’t list many other domestic producers.

Well, it turns out, there are a couple of reasons. For one, conditions are important. While the stalks are grown indoors, the crowns need to develop in the fields, and they can’t handle intense temperatures. Tim says Washington’s wet and mild climate and nitrogen-rich soil are perfectly suited to the task, but knows of attempts in Michigan and California that have failed (too cold and too hot, respectively).

Secondly, it’s quite labor-intensive. Documentary photographer Martin Parr profiled the remaining Yorkshire rhubarb farmers, and saw firsthand the effort required:

The romantic story of the rhubarb is about how they pick it by candlelight. But what people forget is that the labour is completely back-breaking. One of the guys I spoke to used to be a miner, and he said that rhubarb was harder work than being down the mine.

Forced rhubarb needs no explanation in the U.K.; it's an ingredient celebrated for its culinary and cultural contributions. And I mean celebrated. In Wakefield, there is an annual rhubarb festival, complete with rhubarb cooking demonstrations, master classes, and face painting by the "rhubarb team". Two-hour tours of the forcing sheds are open to the public. Photographer Martin Parr's exhibition on forced rhubarb farmers just opened at the Hepford Wakefield Art Gallery.

On this side of the pond, however, most of us are still in the proverbial forcing shed (that is, the dark) about this product. I would be, too, if not for my Eataly source and her knowledge of Internet rhubarb videos.

Make up for lost time:

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On Black & Highly Flavored, co-hosts Derek Kirk and Tamara Celeste shine a light on the need-to-know movers and shakers of our food & beverage industry.

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See what other Food52 readers are saying.

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Annie Crabill

Written by: Annie Crabill


EL February 12, 2016
Cool article. Two questions:

1. Do they replant the rhubarb after forcing, or just throw the plants away?

2. (more of a comment than a question). this leads to the question of whether one could "hill" outside grown rhubarb (I have 4 plants growing that I could "hill") and get the same tender/sweetness as the forced variety in season.

For you non-gardeners, hilling is building up dirt around a plant to keep it from exposure to light (or covering in another way) and is commonly done with leeks, celery (for similar reasons to the rhubarb) and asparagus. Endives and dandelions are also covered.
Annie C. February 12, 2016
Both good questions, and ones I'm not sure I know the answers to. As far as your "hilling" question, I think temperature is key, so that might depend on your climate!
Annie E. February 10, 2016
I just picked up some rhubarb in Auburn, Washington which is very close to Puyallup. I bet it is from the Richter Family Farms. I had no idea about forced rhubarb, but I am, as I type, baking rhubarb pie with it. I moved here from Minnesota a little over a year ago and always had to wait for rhubarb which drove me crazy. My mind is blown!
Bob February 10, 2016
It's just "Yorkshire", not "Yorkshire County", but the rhubarb is indeed wonderful.
Annie C. February 10, 2016
Thanks for pointing that out, Bob! The article has been updated to reflect that change.