WEBVTT - How Can Rhubarb Grow in the Dark? 0:00:01.840 --> 0:00:07.560 Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff 0:00:07.600 --> 0:00:12.360 Lauren Vogel bomb here. Rhubarb is a vegetable that is 0:00:12.400 --> 0:00:16.320 often eaten like a fruit. It looks like if celery 0:00:16.400 --> 0:00:19.279 got into a tub of watermelon colored kool aid, and 0:00:19.400 --> 0:00:23.079 tastes like the very sourst combination of apple and orange 0:00:23.120 --> 0:00:26.840 that you can imagine. Its leaves are a little bit toxic, 0:00:27.080 --> 0:00:30.320 and the plant was used medicinally for millennia before it 0:00:30.400 --> 0:00:34.919 really caught on as an ingredient in pies. A culinary 0:00:35.000 --> 0:00:37.680 rhubarb is a hybrid of at least a couple species 0:00:37.720 --> 0:00:42.800 within the genus room. The plant most likely originated in Asia, 0:00:42.840 --> 0:00:45.000 was a star on the Silk Road, and has now 0:00:45.040 --> 0:00:48.080 grown in temperate regions around the world. It likes the 0:00:48.120 --> 0:00:50.440 weather to stay a little bit chilly, even in the summer. 0:00:51.640 --> 0:00:55.880 There's a famous rhubarb triangle in Yorkshire, England, an area 0:00:55.960 --> 0:00:59.000 of just nine square miles that's twenty three square kilometers, 0:00:59.320 --> 0:01:02.920 known for produce seing early tender crops grown in complete 0:01:03.000 --> 0:01:07.759 darkness and traditionally harvested by candle light. Here in the US, 0:01:08.040 --> 0:01:10.840 most of the rhubarb that is commercially cultivated comes from 0:01:10.920 --> 0:01:15.200 the Pacific Northwest. For the article. This episode is based 0:01:15.200 --> 0:01:18.120 on how Stuffwork. Spoke with Tim Richter, a fourth generation 0:01:18.319 --> 0:01:21.440 farmer of rhubarb in Washington State and the owner of E. G. 0:01:21.640 --> 0:01:26.560 Richter family farm. Richter's great grandfather went west from Minnesota 0:01:26.600 --> 0:01:28.959 during the Gold Rush, but he missed the boat on 0:01:29.000 --> 0:01:32.680 that opportunity and instead started farm growing rhubarb and other 0:01:32.720 --> 0:01:35.960 crops in the late eighteen hundreds. The farm has been 0:01:36.000 --> 0:01:39.120 passed down through the generations, and Richter's son now also 0:01:39.200 --> 0:01:43.679 helps run it. Richter said, they kind of like the moist, 0:01:43.760 --> 0:01:46.520 mild climate, and that's what you've got in Washington a 0:01:46.600 --> 0:01:50.200 specifically western Washington. When you get too much sun and 0:01:50.240 --> 0:01:53.200 too much heat, the rhubarb can grow, but what tends 0:01:53.240 --> 0:01:56.120 to happen it loses the color the stocks start to 0:01:56.160 --> 0:02:01.240 turn quite green. Lots of sun light can also cause 0:02:01.320 --> 0:02:04.760 rhubarb to grow tougher and more tart, which is why 0:02:04.840 --> 0:02:09.840 some is grown and harvested indoors in darkness. Sunlight is 0:02:10.000 --> 0:02:13.880 usually necessary to get plants which use photosynthesis for energy 0:02:13.919 --> 0:02:19.359 to grow. This indoor rhubarb, usually called forced rhubarb, relies 0:02:19.440 --> 0:02:22.480 on a trick of how the plant stores energy year 0:02:22.520 --> 0:02:27.480 after year. Rhubarb is a perennial plant, which means it 0:02:27.480 --> 0:02:30.800 will come back year after year. When you grow rhubarb 0:02:30.840 --> 0:02:34.440 from seeds, the plant will send multiple stalks up, each 0:02:34.520 --> 0:02:38.119 topped with a broad, frilly leaf, and underground it will 0:02:38.120 --> 0:02:41.080 develop a rhizome off of which the plant's roots grow. 0:02:42.280 --> 0:02:44.840 A rhizome is a sort of storage container that some 0:02:45.000 --> 0:02:48.280 plants have evolved to save up water and sugars and 0:02:48.320 --> 0:02:51.880 other nutrients for potential lean times when water or sunlight 0:02:52.000 --> 0:02:56.359 might be scarce. Ginger and turmeric are types of rhizomes, 0:02:56.760 --> 0:02:59.680 and as with those plants, you can propagate rhubarb by 0:02:59.720 --> 0:03:04.160 plant a cutting from a rhizome. Normal field rhubarb will 0:03:04.200 --> 0:03:07.200 grow stalks every year that you can harvest or let 0:03:07.240 --> 0:03:11.120 die back during the winter. For forced rhubarb, you then 0:03:11.200 --> 0:03:15.040 move the rhizome indoors into a prepared hothouse with controlled 0:03:15.280 --> 0:03:20.640 and deeply limited lighting. A Richter explained, you grow this 0:03:20.760 --> 0:03:23.480 plant in the field for two years until the rhizome 0:03:23.520 --> 0:03:27.200 becomes a pretty good sized ball, about one hundred pound ball. 0:03:27.960 --> 0:03:30.440 Then we file those out of the soil in December 0:03:30.480 --> 0:03:33.240 once the plants gone dormant, and then we bring them 0:03:33.280 --> 0:03:36.800 into these buildings, stack them in these aisles, close the 0:03:36.840 --> 0:03:39.120 doors and turn on the heat with a little water, 0:03:39.520 --> 0:03:42.280 and it starts shooting up the stalk in search of light. 0:03:42.880 --> 0:03:47.640 And then we come along and pull it off. Without light, 0:03:47.880 --> 0:03:51.320 the rhizomes spend all that stored energy, sending up stalks 0:03:51.480 --> 0:03:55.720 super quick. Supposedly, you can actually hear them crackling as 0:03:55.720 --> 0:04:00.120 they grow. And because the plants grow in darkness, they 0:04:00.280 --> 0:04:03.240 don't develop the chlorophyll that would normally turn the leaves 0:04:03.240 --> 0:04:06.880 and stalks green. The leaves come out yellow, and the 0:04:06.880 --> 0:04:11.440 stalk's a brilliant ruby red. Forced rhubarb tends to be 0:04:11.480 --> 0:04:14.320 more tender and sweeter than its fellows from the field. 0:04:14.880 --> 0:04:17.960 As field rhubarb is exposed to normal light, the stalks 0:04:18.000 --> 0:04:21.400 often develop a green tinge or stripes, and will have 0:04:21.480 --> 0:04:26.440 a slightly stringier texture and more puckery flavor. Field rhubarb 0:04:26.480 --> 0:04:29.640 also typically comes in later in the growing season, arranging 0:04:29.680 --> 0:04:33.960 into early summer. There's nothing wrong with either, though you 0:04:34.000 --> 0:04:37.080 will pay more at the market for the fussier forced type. 0:04:38.600 --> 0:04:42.520 No one is really sure where today's tasty rhubarb comes from, 0:04:42.560 --> 0:04:46.000 but researchers think that these culinary hybrids were developed from 0:04:46.160 --> 0:04:51.160 earlier medicinal types around the seventeen hundreds in Europe. Rhubarb 0:04:51.240 --> 0:04:53.800 was very popular in places like the US and the 0:04:53.920 --> 0:04:56.920 UK from the mid eighteen through the mid nineteen hundreds, 0:04:57.240 --> 0:05:00.760 but it's fallen off a bit since then. With so 0:05:00.960 --> 0:05:04.200 much new to US produce coming in from across the world, 0:05:04.440 --> 0:05:06.479 it can be hard for rhubarb to compete in the 0:05:06.520 --> 0:05:10.200 global market. A plus, the tart flavor means that most 0:05:10.200 --> 0:05:13.200 recipes call for rhubarb to be cooked down, often with 0:05:13.279 --> 0:05:16.120 lots of sugar, which can make it less appealing than 0:05:16.160 --> 0:05:19.760 produce that's ready to eat right out of hand. But 0:05:20.120 --> 0:05:23.360 some people like Richter, will rave about eating a raw 0:05:23.400 --> 0:05:26.360 stock dipped in a bit of sugar, And in general, 0:05:26.480 --> 0:05:29.400 there are still plenty of rubarb enthusiasts out there, as 0:05:29.520 --> 0:05:33.480 seen in the plethora of rhubarb centric festivals from Wakefield, 0:05:33.480 --> 0:05:37.400 England in the Rhubarb Triangle, to Pennsylvania Dutch Country, to 0:05:37.640 --> 0:05:41.000 the city of Lanesboro also known as the rhubarb Capital 0:05:41.080 --> 0:05:45.559 of Minnesota. And if you want to find some most 0:05:45.640 --> 0:05:48.960 large grocery stores carry it, either fresh or frozen. You 0:05:49.040 --> 0:05:51.680 might find it in bins in the crisper section looking 0:05:51.920 --> 0:05:55.640 like long leafless stocks of charred which it is distantly 0:05:55.720 --> 0:06:00.680 related to, and yes, it is technically a vegetable. Rhubarb 0:06:00.760 --> 0:06:04.599 stalks are botanically what's called pettioles, which are the bit 0:06:04.640 --> 0:06:07.400 that connects a leaf to the stem or main body 0:06:07.440 --> 0:06:11.960 of a plant. These are usually tiny. Rhubarb stocks are 0:06:12.000 --> 0:06:18.080 just wildly overgrown pettioles. Culinarily, many cultures use rhubarb as 0:06:18.120 --> 0:06:20.920 a fruit, a cooked down with sugar and maybe other 0:06:21.000 --> 0:06:24.640 things like strawberries or apples, perhaps in a jam, in 0:06:24.680 --> 0:06:27.159 a sauce for ice cream or custard, or as a 0:06:27.160 --> 0:06:32.280 filling for pie. It's sometimes called the pie plant. In 0:06:32.360 --> 0:06:35.560 nineteen forty seven, a US customs court in Buffalo, New York, 0:06:35.640 --> 0:06:39.600 even declared rhubarb to legally be a fruit, mostly for 0:06:39.760 --> 0:06:43.400 tax purposes. The import tax on fruits was lower than 0:06:43.400 --> 0:06:47.240 those on vegetables, and the successful argument went that most 0:06:47.279 --> 0:06:51.280 Americans use it as a fruit anyway. It doesn't have 0:06:51.320 --> 0:06:55.000 to be relegated to dessert, though. Recipes from Eastern Europe 0:06:55.000 --> 0:06:58.839 and Western Asia often use rhubarb in savory dishes, bringing 0:06:58.880 --> 0:07:01.960 a bright edge to things like rich stews and roasted meats, 0:07:02.279 --> 0:07:05.400 either as an ingredient or a sort of relish or chutney. 0:07:06.040 --> 0:07:09.560 Think of how you might use cranberry or lemon. While 0:07:09.600 --> 0:07:11.600 I was doing the reading for this episode, I found 0:07:11.600 --> 0:07:14.960 recipes for a rhubarb chicken bake and for a rhubarb 0:07:15.040 --> 0:07:18.080 potato gratten that I just cannot get out of my head. 0:07:19.160 --> 0:07:23.600 But however people eat rhubarb, they never or should never 0:07:23.840 --> 0:07:27.000 eat the leaves because those are toxic enough that you 0:07:27.080 --> 0:07:30.280 don't want to mess with them. They contain a potent 0:07:30.320 --> 0:07:34.120 concentration of oxalic acid, which is a compound that binds 0:07:34.160 --> 0:07:36.880 to calcium in our blood and thus makes that calcium 0:07:36.960 --> 0:07:41.080 unavailable for your body to use. You have to eat 0:07:41.120 --> 0:07:44.520 something close to like seventeen pounds or eight kilos to 0:07:44.600 --> 0:07:47.960 actually poison yourself, but even a few leaves can cause 0:07:48.040 --> 0:07:53.000 nausea and other digestive troubles. Note that the whole plant 0:07:53.120 --> 0:07:57.520 does contain some amount of cathartic and laxative compounds, which 0:07:57.600 --> 0:08:00.400 can make it easier to poop, which is part of 0:08:00.440 --> 0:08:05.200 what medicinal rhubarb was so prized for. Ancient Chinese and 0:08:05.280 --> 0:08:09.760 possibly Siberian peoples started cultivating rhubarb over five thousand years ago. 0:08:10.880 --> 0:08:14.200 The yellow rhizome in particular was used in traditional Chinese 0:08:14.280 --> 0:08:19.080 medicine as a digestive aid. Through this use, dried rhubarb 0:08:19.200 --> 0:08:22.480 became a luxury good on the Silk Road around the 0:08:22.480 --> 0:08:25.160 early fourteen hundreds. The best stuff went for as much 0:08:25.200 --> 0:08:29.000 as saffron or cinnamon. It was so popular as a 0:08:29.040 --> 0:08:32.320 medicine that from these sixteen through the eighteen hundreds the 0:08:32.400 --> 0:08:36.400 romanov Empire monopolized the cultivation and trade of it around 0:08:36.440 --> 0:08:38.679 Europe and made a lot of money while they were 0:08:38.679 --> 0:08:43.000 at it. But starting in the seventeen hundreds, as seeds 0:08:43.040 --> 0:08:46.920 and rhizomes got out and farmers developed new hybrids and 0:08:47.200 --> 0:08:51.240 sugar became more available, rhubarb became more widely known as 0:08:51.320 --> 0:08:54.960 a food. It was featured around the coronation of Queen 0:08:55.040 --> 0:08:59.199 Victoria in eighteen thirty seven, and the aforementioned Rhubarb Triangle 0:08:59.240 --> 0:09:02.280 started up in your sure. At one point there was 0:09:02.320 --> 0:09:06.280 a designated train named the Rhubarb that delivered stocks from 0:09:06.280 --> 0:09:11.000 the triangle to King's Cross in London every day. By 0:09:11.000 --> 0:09:13.920 the late eighteen hundreds, rhubarb but was firmly entrenched as 0:09:13.960 --> 0:09:17.000 a dessert plant, not a medicine at all in the UK, 0:09:17.280 --> 0:09:22.800 the US and beyond, but Today, researchers are studying extracts 0:09:22.800 --> 0:09:26.560 of rhubarb for all kinds of potential medicinal properties, from 0:09:26.920 --> 0:09:30.760 yes digestive aid to helping control blood sugar levels, to 0:09:30.960 --> 0:09:35.480 protecting against the long term effects of Alzheimer's to antiviral treatments. 0:09:36.640 --> 0:09:41.040 Our bodies are complicated and more research is necessary. Definitely 0:09:41.120 --> 0:09:44.760 consult a healthcare professional, which I am not before ingesting 0:09:44.840 --> 0:09:49.280 a medicinal dose of anything, but I do feel pretty 0:09:49.280 --> 0:09:54.199 safe clearing you to try a slice of that pie. 0:09:57.240 --> 0:10:00.839 Today's episode is based on the article Rhubarb Poisonous veggie 0:10:00.920 --> 0:10:03.720 you can Totally Eat on HowStuffWorks dot Com, written by 0:10:03.760 --> 0:10:07.520 Terry year Lagatta. Brainstuff is production of iHeartRadio in partnership 0:10:07.559 --> 0:10:10.080 with HowStuffWorks dot Com and is produced by Tyler Klang. 0:10:10.440 --> 0:10:13.720 With four more podcasts from iHeartRadio, visit the iHeartRadio app, 0:10:13.840 --> 0:10:16.880 Apple Podcasts, or wherever you listen to your favorite shows.