The sweet secret of corn is in the harvesting

URBAN FARMER:Sweetcorn must be picked at just the right time, writes Fionnuala Fallon

THERE CAN be few vegetables as versatile or as useful as corn, that magical golden grain that can be transformed into a fuel (Ethanol), an animal feed, a sweetener (corn syrup, dextrose, fructose), a laundry starch, or even into biodegradable packaging materials and plastics. But its usefulness as a crop, or more particularly as a cheap food sweetener, is not without its critics, who call it the “devil’s candy” and blame it for rising levels of obesity and diseases such as diabetes. There’s even a Facebook campaign to stop the use of HFCS (High Fructose Corn Syrup) that’s so high profile it featured in a report by the

New York Times

earlier this year.

Garden historians also point out that newer cultivars of sweet corn (itself a natural mutation of the less sweet field corn) are being bred to be supersweet, with the sugar content of modern cultivars up to four times that of the traditional varieties once cultivated by native American tribes over two hundred years ago. The other problem with such modern supersweet varieties is that their sweetness is at the expense of flavour, something that OPW gardeners Meeda Downey and Brian Quinn discovered for themselves last year.

“This year, were growing an early variety called Sundance, which ripens well even in poorish weather. But last summer, we grew a different, supersweet variety called Earlibird which has two to three times the sugar level of ordinary varieties. Even though it’s a good storer, we didn’t really think that much of the flavour”, explains Brian. “So we went back to our original favourite, Sundance, which we think is a lot tastier.”

The gardeners filled an entire section of the walled garden (one of 16 subdivisions or separate plots within its 2.5 acres) with sweet corn (1,200 plants) and are very chuffed with the results, with each plant producing somewhere between two to four cobs.

“Once you get it growing in the ground, sweet corn is a relatively low-maintenance crop”, comments Brian. We raised the young plants from seed in the heated glasshouse and then planted them out in early June, when they were about a foot tall and once there was no risk of frost.

Since then, we’ve done nothing to them other than to keep an occasional eye out for weeds or slug damage – but neither has been a real problem.”

Low-maintenance the vegetable may be while it’s in the ground, but it’s a different story once it comes to harvesting.

“You need to harvest sweet corn at just the right moment”, admits Brian, pulling a cob from a plant and peeling back the green sheath from around its golden kernels.

“There’s a certain point when you can tell that it’s ready, when the tassels or the ‘silks’ have gone dry and brown and when, if you press down firmly on the kernels with your thumb, you should see a milky white juice squirting out of them. The kernels should also be a pale golden colour, not a deep yellow”, he explains as he tests the cob for ripeness.

“If the juice is watery, it’s not ready. But if it’s pure white, and kind of floury or thick, then it’s overripe. It’s all about the timing.”

The problem as regards harvesting the sweet corn in the walled kitchen garden is that the OPW gardeners are not the only ones waiting for that perfect moment. There’s also an ever-present army of crows (or more correctly, a “murder” of crows) who are eagerly anticipating the almost-ripe crop.

“Ideally, we should net the plants at this stage to protect against birds but we’ll be harvesting the cobs in the next few days so we won’t bother. Once they’re picked, though, the cobs should be eaten very quickly, ideally in a matter of hours and before the sugar in the kernels turns to starch.”

So once harvested, what’s the perfect way to eat a ripe cob of sweet corn? Brian reckons that they’re best eaten as he once tasted them on a holiday in Greece, freshly harvested, grilled on a barbeque and then soaked in melted butter and a sprinkle of salt. Garden writer Sarah Raven does something similar, roasting her sweet corn with the husks intact before serving the smoky sweet cobs with either a thyme butter or chilli jam. The food writer Nigel Slater is also in agreement, explaining that grilling intensifies the flavour of the kernels rather than their sugar content.

"A while over the coals is my preferred way with what could otherwise be a simple sugarfest", he writes in his book The Kitchen Diaries.

All of which goes to show you that, despite what modern vegetable breeders believe to the contrary, a high sugar content is definitely not the sweetest thing when it comes to eating the perfect corn on the cob.

The OPW’s Victorian walled kitchen garden is in the grounds of the Phoenix Park Visitor Centre, beside the Phoenix Park Café and Ashtown Castle. The gardens are open daily from 10am to 4pm

Fionnuala Fallon is a garden designer and writer

What to sow, plan and do now

Sow: Beetroot, broccoli raab, carrots (look out for variety Nanco, Nantes Frubund, endive, kales (as CCA), kohl rabi, Florence fennel, komatsuna, land cress, lettuce, mibuna, mizuna, mustards, pak choi, spring onions, Chinese cabbage, spring cabbage, radish, rocket, winter spinach, Swiss Chard, turnips, winter purslane

Plant: Sprouting broccoli, chicory, French beans, Brussels sprouts, cabbages, calabrese, cauliflowers, kale, leeks, second-cropping potatoes (eg. Carlingford).

Do: Continue harvesting, continue sowing seed and pricking out/ thinning seedlings, weed/ hoe beds, net young brassicas, soft fruit and fruit bushes, cover carrots with Bionet, spray non-blight resistant potatoes with Dithane to protect against blight, pinch out side basal shoots and stake tomatoes, feed tomatoes, celeriac, celery, pumpkins, watch out for garden pests.