Planking's Overrated

By Robert L. Wolke
Wednesday, October 12, 2005

We recently purchased some cedar boards from Wegmans for grilling salmon. The result was delicious and moist, but I am wondering if cooking on a cedar board can really affect the flavor of the fish. Also, Wegmans boards are very expensive, so I am wondering if I can just purchase cedar shingles or planks at a lumber store. Has lumber yard cedar been treated with chemicals that would make it unsafe for food use?

Like you, I also wondered about the flavor-enhancing powers of wooden boards. So I went to Home Depot and bought six feet of 1-by-10-inch cedar board, but not before being assured by the lumber professionals that it had not been treated with any toxic chemicals to retard flammability, weathering, insect damage or rotting, as, for example, the cedar roofing shingles had been. After cutting it into about 14-inch lengths, lightly sanding them and treating them with olive oil, I was ready to plank some salmon.

Folklore has it that the Pacific Northwest Indians cooked whole or filleted fish by fastening them to cedar or alder boards, propped up vertically around a fire. Somewhat cynically, I can't help suspecting that they did that because they didn't have gas grills or stainless steel frying pans, rather than because the wood imparted gourmet flavors to the fish. And by the way, did they have lumber mills?

Nevertheless, today's inhabitants of British Columbia, Washington and Oregon hold fast to the tradition and swear that a cedar or alder plank imparts exquisite flavors to the salmon. And as you discovered, cooking equipment manufacturers have been quick to fill the demand.

Following the instructions of several cooks in the Northwest, I soaked one of my cedar planks for a couple of hours in a few gallons of water (eschewing the tablespoon of sea salt specified by one chef), laid my salmon on it, placed the board on my hot charcoal grill and closed the lid. Of course, the salmon cooked thoroughly, even on its underside, enclosed as it was in an oven. And of course, the wood soon dried out and smoked copiously.

So how did the salmon taste? Smoked. Period. It was a result that could have been achieved by throwing a few wood chips on the fire.

But using the plank made me feel so much more hip. And perhaps because of the cedar's presence, I didn't see a single moth.

I've run across a strangeness in the past few months that perhaps you can explain. I have a nitrous oxide cartridge-powered whipped cream maker. I make half-pint batches, usually with 1 teaspoon of sugar to a half-pint of heavy cream. A half-pint, at my usage rate, usually lasts a bit over two weeks.

Lately, however, after only about three days in the refrigerator, the cream in the pressure bottle turns to a foamy gel, too thick to squirt out the nozzle. I'm buying the same brand of cream that I've been using for several years, but lately all I can find is ultrapasteurized. Could the ultrapasteurizing process have changed?

You have divined the answer your own question. Yes, it's the ultrapasteurization.

A bit of explanation first, however, for readers who are not as technologically sophisticated as you and who whip their cream with elbow grease. (And we're talking here about real cream, not the hydrogenated vegetable fats sold in aerosol cans of "whipped toppings.") The purpose of whipping or beating cream is to incorporate as many air bubbles into it as possible, converting it into a smooth, velvety, spoonable foam. In principle, one can beat any liquid into a foam, but the air bubbles would quickly coalesce, breaking down the foam. To create a lasting foam, we need something that will surround the bubbles and keep them from coming together. That something is the milk fat -- lots of it. Cream containing less than about 30 percent fat will not whip to a stable foam.

Whipping breaks down the fat into tiny globules that tend to associate with one another to form chains and clusters that then form walls around the air bubbles, keeping them from coalescing. The fat globules can do this job best when they are partially crystallized (solidified); that's why chilling the cream and the utensils is essential to effective whipping.

But why nitrous oxide as the whipping power? Nitrous oxide is a tasteless, odorless, nonflammable, bacteria-inhibiting gas that, when compressed into a can of cream, dissolves to a great extent in the cream. Then, when the pressure is released, the gas bubbles furiously out of the cream, agitating it violently enough to whip it. The resulting foam will contain tiny bubbles of nitrous oxide instead of air, but they're harmless.

Now for your problem. An essential part of the whipping process that I haven't yet mentioned is that in order to remain independent of one another, the fat globules must be surrounded by membranes of casein and other milk proteins. Without this protein coating, the globules would be unable to construct those protective walls around the gas bubbles.

Although ultrapasteurization -- heating the cream to about 280 degrees for two seconds -- kills more germs than regular pasteurization (145 to 150 degrees for 30 minutes), it denatures the proteins slightly, weakening their ability to perform their globule-coating duties. The cream then not only takes more force and time to whip but also will break down sooner than ordinary pasteurized whipped cream. And that's what happened inside your whipped cream dispenser.

Unfortunately, almost all milk and cream these days is ultrapasteurized. So you just have to live with it. Finish off the whole batch of whipped cream within your three-day window.

Robert L. Wolke ( is professor emeritus of chemistry at the University of Pittsburgh. His latest book is "What Einstein Told His Cook 2, the Sequel: Further Adventures in Kitchen Science" (W.W. Norton, 2005). He can be reached

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