You can't beat the perfect mash

By Andreas Viestad
Special to The Washington Post
Sunday, November 22, 2009

Food lovers come in all forms: snobs, egalitarians, conformists, neophytes, neophobes. Sometimes there seems to be very little that unites them. But all the food lovers I know have one thing in common: an almost obsession-like love for (or is it perhaps a crush on?) mashed potatoes.

A few years ago I was throwing a dinner party, and when I found out one of the guests was a famous chef, I spent ages pondering the menu. It had to be sophisticated enough to show I was making an effort, but still casual and easy enough to show I was not trying to compete with the master. I am not sure whether I managed that delicate balance; perhaps the foie gras with truffles was over-the-top, and maybe the braised cabbage was too humble. But when I noticed that the guest of honor had helped himself to a third serving of the potato puree, I stopped worrying.

Mashed potatoes or potato puree is a dish everyone can make. It demands so little: Boil some potatoes and crush them with whatever you have at hand: a potato ricer, a fork or the backside of a wooden spatula. The transformation from plain boiled potatoes to a dish with its own merit needn't take more than a minute. If the potatoes are good, and if you add a little milk, a lump of butter or some cream, few people would not appreciate or even love the result.

That such a dish can be made simply or with elegance is evidence of its versatility. However, the process of making good mashed potatoes does have its demands. For every notch more advanced you decide to make your mashed potatoes or potato puree, the preparation becomes three or four or even 10 notches more challenging. (There is no firm and established boundary for when mashed potatoes become potato puree.) You have to know which kinds of potatoes to use and which kitchen equipment works best. But most of all it is about knowledge and technique. Good cooks can transform boiled potatoes into a feathery-light puree. Cooks who are overeager or inattentive risk ending up with a sticky mass of something more resembling wallpaper glue than gastronomy.

The makeup of the potato is key. Potatoes, as we all know, contain a lot of starch, which can behave in many ways depending on how we treat it. It can form long, gluey molecules, gels or emulsions. Boiled potatoes left in water will start to jellify and may even increase in volume, becoming swollen and watery. If a potato puree is watery, it will become sticky. That is why it is important to let the potatoes drain for a couple of minutes in a colander immediately after they are cooked.

When potatoes meet milk, on the other hand, the starch reacts differently. Mashing or pureeing potatoes with milk, cream or butter, all of which contain casein proteins, limits the swelling of the starch and leads to a smoother, less sticky consistency. Which of the three you use will determine the richness of the dish. (This leaves non-dairy people with a bit of a problem, and the desire for a potato puree cannot easily be satisfied. A root vegetable puree or mash with only a small proportion of potato is probably the best alternative.

Potatoes also need a gentle hand. Cooks who are very strong, energetic or aggressive, and anyone who has tried to make mashed potatoes in a food processor, will end up with an unappetizing, gluey mass as the cells are ruptured and the starch molecules are beaten together into long chains. A hand-held electric mixer is a little better: The beater blades are not sharp enough to do great damage to the cells. But even though it is less brutal than a food processor, it is still not something I recommend. I always whisk by hand to have full control during this last, crucial stage.

To recap, keep these maxims in mind when making mashed potatoes:

1. Water is no friend.

2. Starch needs respectful management.

3. Dairy products make magic.

The modern cook who has understood this best is probably the French chef Joël Robuchon (who 20 years ago was named chef of the century in France by the Gault Millau guide and whose dozen restaurants have a total of 25 Michelin stars). It would not do him enough credit to say that he owes his fame to his velvety, super-rich potato puree. But is not far from the truth, either. "He realized early on that if you give people potatoes, potatoes and more potatoes, they'll be eternally grateful, forever fulfilled," writes Patricia Wells in her 1991 book on Robuchon's cooking.

I traveled to Paris last month to sample the puree at L'Atelier de Joël Robuchon: a pilgrimage in the search of the perfect mash. It was a lot like any other good potato puree I have tasted. Only much, much better. It was soft and creamy; as rich as Croesus, yet as light as snow.

"We have one cook who does nothing else," said L'Atelier's executive chef, Axel Manes.

There is no secret recipe: only the serious, even extreme, application of the three aforementioned principles. Robuchon potatoes are cooked in lightly salted water and then drained. For smooth, velvety structure without the risk of tangled starch molecules, the potatoes are pressed through a very-fine-mesh sieve. Not once, not twice, but three times. More water is removed by heating the riced potatoes in a pot over low heat. Hot milk is added, then cold butter is gradually beaten in with a whisk to form a creamy and airy emulsion.

It is impressive, yet quite simple. Still, it is not something you would make every day, even if you had time. Apart from the craftsmanship and the gentle but firm treatment of the potato, the difference between Robuchon's potato puree and most others is the amount of butter used. In fact, I have heard food scientists argue that the potato puree is really an emulsion, as closely related to the classical French sauces as to the mash we all know.

Exactly what that amount was I was unsure of. Before I left L'Atelier, though, chef Manes came to say goodbye, and I had the opportunity to find out.

"You use quite a lot of butter, don't you?" I asked him.

"Oh, yes! A lot!"

"How much?"

"Well, let me see. Every day we serve around 35 pounds of potato puree. For that we need 17 pounds of potatoes, and around 17 pounds of butter."

It caused me to suddenly remember the title of Phyllis Richman's culinary mystery novel: "The Butter Did It."

Robuchon's potato puree is probably the most sublime combination of a modest American spud and the extravagance of French cuisine. I am thankful that I now know how to achieve the perfect mash, yet I often end up settling for a little less.


Simple Mashed Potatoes

Rich, Velvety Potato Puree

Viestad, author of "Where Flavor Was Born" and host of the public television series "New Scandinavian Cooking With Andreas Viestad," can be reached at or His column appears monthly.

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