The traditional approach to creamy, smooth potatoes is to add so much cream and butter that you can hardly taste the potatoes anymore. But, we’ve discovered how you can make velvety-smooth potatoes without adding any cream at all! The secret ingredient is diastatic malt powder, an ingredient available from specialty baking or brewing supply stores that converts potato starches into sugars, leaving no trace of gumminess or graininess.
Potato starch granules are big: up to a tenth of a millimeter in diameter. That’s large enough for your tongue and teeth to detect. The microscope image above, taken by our very own Nathan Myhrvold, reveals the potato starch granules (stained red by iodine vapor) surrounded by the potato’s cell walls (stained blue).
Diastatic malt powder is made from a grain containing the enzyme diastase. This enzyme speeds up the rate at which starches breakdown into sugars. When you set this enzyme loose on potato starches, it actually splits the giant starch molecules into much smaller sugar molecules, smoothing the puree at the microscopic level and eliminating the graininess associated with dairy-free potato purees.
- Diastatic malt powder is available online, as well as at specialty baking and brewing supply stores.
- If you don’t have a sous vide machine, in step 8 you can place the bag of potato puree in a pot of water on the stove, or in a cooler filled with hot water. Just try to keep the water temperature as close to 52 °C / 126 °F as possible.
- Raising the temperature of the puree in the final step of the recipe halts the enzymatic activity.
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