The perfect posset formula? Minimal ingredients, maximum flavors, and just the right citrusy tartness!
Happy Thursday, dear friends 🙂 Earlier this week I made a posset for an Instagram challenge focused on spring cooking and seasonal flavors. It was a wonderful opportunity for me to learn the history of posset, a quintessential British treat (mentioned by Shakespeare in some of his plays!), as well as to highlight a rather oddly-shaped, but oh-so-delicious fruit currently in season: sumo citrus aka shiranui or dekopon, as it is known in the country of its origin, Japan.
As Andee Gosnell explains in Food & Wine magazine, sumo citrus are a hybrid of three varieties: mandarin oranges, satsumas, and navel oranges. “These large fruits, slightly smaller than grapefruit, have wrinkled skin that is easy to peel and an incredibly sweet flavor compared to other citrus. They can register up to 18 Brix on the sweetness scale, compared to 12 for satsumas, according to The Guardian. The “sumo” name comes from the top bulb’s resemblance to a sumo wrestler’s hairstyle.”
The history of this fruit is fascinating: “In the 1970s, Japan’s Ministry of Agriculture set out to create the gold standard of citrus to reinvigorate the country’s fruit market. The goal: A less acidic and seedless fruit that was easy to peel. By the 1990s, shiranui citruses were popular throughout Japan. The first seedlings did not arrive in the U.S. until 1998. They debuted on supermarket shelves at Whole Foods in 2011” (Andee Gosnell, “Meet Sumo Citrus, the Short-Lived Fruit That Celebrities and Chefs Swear By”)
I wanted to showcase sumo citrus in a luxurious yet minimalist dessert, and I thought Nigella Lawson’s posset recipe would suit this task perfectly 🙂 But, what is posset?
“In the Middle Ages, posset was a milky medicinal drink, potable but not especially appealing. Today’s posset is something altogether different: a chilled dessert with an impossibly satiny texture, like the silkiest mousse or pudding, but easier to make since it contains only cream, sugar, and fresh lemon” (Annie Petito, “How to Turn Any Juice into Satiny Posset”)
As Annie Petito explains in the aforementioned article, the acidity of lemon juice is crucial to ensure the posset solidifies and turns out creamy. Petito conducts several experiments with lower acid fruit juices – a fascinating read – and concludes that you can use them to make posset if you also add food-grade citric acid (you can add lemon juice, but that would alter the flavor of the original fruit, sumo citrus in my case) “Dissolve 20 grams citric acid in 30 grams of water—and use it to bring any juice to a pH of 2.6 (the sweet spot to ensure that the posset sets and won’t be too tart)” 
Sumo citrus are sweet and low acid, and I added the citric acid solution to make sure the posset would set properly. The end result had an exquisite velvety texture, infused with delicate tartness. It was a magical treat – made possible thanks to one of the most exciting and enchanting seasonal fruits. I am glad I came across Petito’s article before attempting the posset because I am not sure I would have been successful without the addition of citric acid.
For an equally delicious and super creamy use of seasonal citrus, I recommend panna cotta with candied blood oranges.
Have you ever made posset, and do you have a favorite citrus fruit? Let me know in the comments 🙂
Leave a Reply