As I may have mentioned, I have lately developed a bit of a thing for pea butter. Not some sort of pea-infused dairy butter, but the real deal, the pure green fat of tender garden peas laboriously isolated and concentrated, and spread on toast. I first had it when I was visiting the Modernist Cuisine laboratory/kitchen in Seattle last month, and now I very much want more.
How practical is the high-tech 50-pound Modernist Cuisine cookbook for the amateur cook? Can I make my own pea butter? Here’s what I tried.
Pea Butter on Toast
The Modernist Cuisine kitchen’s pea butter is stunning! Even without the edible flowers.
Serious Sorvall Centrifuge
At the M.C. lab, pea butter is made in a Sorvall RC-5C Plus High-Performance Centrifuge, which whirls pea puree at up to 21,000 rpm until it separates out into three layers: juice, starch, and luscious fat. Even if I had a couple of grand to drop on a used Sorvall for home use, I would be hard-pressed to accommodate the large appliance (center) in my Manhattan apartment.
My Home Kitchen Centrifuge
A tabletop centrifuge, however, was within my budget of cash and space. (Truth be told, I lucked into one for free, but they’re under $100 on eBay.)ACHTUNG!** As the Modernist Cuisine book points out, “Laboratories have been destroyed by centrifuge accidents. The smallest crack in a rotor can lead to catastrophic failure, and the near-instantaneous release of all that energy is like the explosion of a small bomb.” A used centrifuge should be checked out by a trained technician before you run it.
I thawed some frozen peas, added enough cold water to make them puree nicely, and pureed with a blender until I had a thick, smooth green soup. This I funneled into the tubes of the centrifuge. To keep a centrifuge from becoming imbalanced, it’s essential that its payload be symmetrical, so all the tubes had to weigh exactly the same, which I checked on my digital gram scale. That done, I loaded the tubes into the centrifuge and took them for a 30-minute spin.
A pea is about three percent fat. That’s not much. When the Modernist team pulls their whirled peas from the rotor, the fat layer is the smallest by far, but still the three strata are beautifully discrete. Mine had the juice on top and the starch on the bottom for sure, but the crucial thin middle layer of fat was awfully thin and hard to see.
Theirs Versus Mine
One of the difficulties, as the picture makes apparent, is that the Seattle crew is nicely equipped with big half-liter containers to put their peas in (left), whereas my little centrifuge only accommodates 15-milliliter tubes (right), each about the volume of a medium-size sip. As a result, they can spin enough peas in each container to yield a nice substantial layer of butter, while I’m left with just a paper-thin layer that I have to peel carefully out of the tube with a long tool. Six of the 15ml tubes yielded barely a fingernail-sized piece of butter. I had a ways to go.
The big Sorvall centrifuge also incorporates a cooling unit, so they can keep their peas chilled while they spin, which I can’t help thinking makes the fat solidify more and hence layer out better. What if I cleared out a shelf in my fridge and put my tabletop centrifuge in there?
Getting the Butter from the Tubes
I repeated the experiment with a fully chilled centrifuge, and indeed I did get a somewhat thicker layer of pea butter, almost three millimeters in each tube. Still, it took some laborious extracting.
This delicious by-product of the pea-whirling process makes a fine cocktail.
The Final Result
And when we were done, a single centrifuging turned out to yield just enough pea butter to thinly coat a small piece of bread. Still, it was scrumptious, the pure, rich essence of pea. Can I get more pea butter out of my centrifuge? I’m going to keep trying. Adding additional ingredients to the puree might help a little — in particular, pectinase enzyme to break down the peas’ cell walls in advance is almost sure to improve my yield, but I don’t happen to have any pectinase on hand at the moment. Adding sugar and/or salt has been known to produce interesting variations in culinary centrifuge output. In the short term, my best bet though might be to cheat, by using some real cow butter to augment the minimal amount of fat I’m getting from my peas. The cookbook has a recipe in which carrot juice is simmered with butter, then centrifuged to create a bright-orange take on pea butter (carrots have even less fat than peas). I’ll keep you posted.