Panna Cotta is one of those desserts that can be spotted on almost every dessert menu, in every city. After a surge of recent popularity, this once “it” girl has proved her staying power. A chic custard with a little shimmy Gordon Ramsey calls the “chi-chi-lina”, the panna cotta won hearts in the dining room with the simplicity of a comfort food, and has made friends in the kitchen with deceptive ease in preparation. A simple combination of cream, sugar, a little flavor, and some gelatin, and like magic you have a sophisticated dessert on your hands.
It is with the simplest preparations that the most care must be taken, and I have adopted various extra steps to ensure the simple preparation of panna cotta, often a casualty of mediocrity, carries not just a memorable flavor, but a perfect texture. With a simple flavor so easy to achieve, it is in refining the texture that panna cotta becomes a great challenge. Just throwing in the recommended dose of gelatin, throwing the mixture in the fridge to set will get you so-so results, most of the time. However, armed with a little information you can ensure your dessert will stand out each time.
Gelatin itself, we know, comes from animals. Thus it is easy to conceive that gelatin is a protein. Rendered most often from the collegen in the hide of four legged animals, this protein behaves much differently than most we are used to working with in the kitchen. Where as the protein in an egg will respond to heat by unfolding and bonding permanently to neighboring proteins (aka coagulating), the proteins in gelatin respond to heat by releasing their bonds to each other. The unusually long protein chains in gelatin, when cold, bind to each other into a triple helix, which cross link with others to form a web. This web interferes with the movement of the water the gelatin is dispersed in, thus gelling it into a solid.
Many things effect the final texture of a gelatin gelled liquid, particularly the manner in which it is cooled. The warmed liquid, necessary to release the proteins from their initial web and disperse them, is most often immediately placed in the refrigerator and cooled quickly. In doing this, the protein chains bond to each other immediately, and randomly, causing bulky and weak cross sections. By cooling the gelatin slowly, at room temperature, the proteins are allowed to mingle with each other, forming a tighter, more structured web. Thus, if you are creating weaker bonds, you would need more gelatin to set an immediate structure. This gelatin will progressively continue to firm over a period of time, thus the texture you gained the first day will be softer than the texture you have in 4 days. In my restaurant, I want the textures to be the same each day I serve the dish.
The way I have interpreted this information has led to this method. I heat a small amount of milk to dissolved the gelatin in. This sits on the counter until it is at room temperature, which takes about an hour or two, a time that is well within the limits of food safety. It is stirred occasionally, and once it is cool, the remainder of the cream is added.
I never heat the entire amount of the liquid used to make a panna cotta. I have found that in heating the cream, or particularly buttermilk, the texture of the liquid changes, and feels thin on the tongue. This fact I haven’t been able to fully support with reading. Everything I find suggests that the fat globules are encased in a membrane that is strengthened by heating. So I am not sure what about the heating process changes the texture of the cream within the gelled panna cotta. My only guess so far is that the heat will cause the protein clusters bound by caseins which float freely around the fat globules (think of a tiny tiny dust bunnies) to stick to the membrane of the fat globule (like a little dust bunny protective shield), perhaps leaving room for the water molecules to become more active in the cream. And perhaps this increased activity in the water molecules creates the feeling of thinness?
Either way, I can use the tried and true method used by chef’s for centuries, to assume facts by observation. I know because I can see it and feel it with my mouth that heating the entire amount of cream for a panna cotta feels thinner in the final product. And the thinner feel makes the panna cotta feel more like milk jell-o than a chic custard.
Recently, I have been withholding a portion of the cream, and very very carefully whipping it just enough to thicken it. To do this, the cream must be very cold, and have been very cold for a continuous period of time. When you whip cream, you are using the shear force of the whisk to strip parts of each fat globules protective membrane. The exposed fat is now sticky, and will adhere to two things; other naked patches of fat globules, and air bubbles. Thus, the air bubbles introduced by the whisk become encased in damaged globules and are trapped in place. When warm, the fat which is no longer encased in it’s protective membrane, is now capable of leaking out and collapsing the air bubbles. Thus the importance of the cream not only staying cold, but having been cold for quite some time.
What we are trying to do is not add too many of these air bubbles, and definitely not large ones created by pounding a whip into the cream. Rather, I whisk slowly back and forth by hand, standing in my walk in refrigerator if possible. I am encouraging the fat globules to stick to each other rather than encase brittle air bubbles.
To steep flavor into your product, I either employ a cold infusion over a period of 24 to 48 hours often with fresh mint, tea leaves, coffee and whole spices, use a liquid addition to the panna cotta like a pulled shot of espresso, orange flower water, and liquors, or steep the flavor into the small amount of liquid heated to melt the gelatin.
And finally, I always use sheet gelatin. Those of my readers that work in professional kitchens will know this product well. Granulated gelatin is second rate. The amount of gelatin and the quality of the gelatin within the granulated form varies. The powder can contain a high amount of broken protein that will never re-bond into the triple helix’s that create the web like junctions. It can contain more or less of viable proteins from batch to batch, creating stronger and weaker gels than you expect. Plain and simple, it’s inconsistent. Unfortunately, it’s the only gelatin readily available to the average cook. I highly recommend finding a source for sheet gelatin if you plan to use much of it at home.
So after a long winded post, I will provide a step by step recipe for a panna cotta perfect for the fruitless season arriving soon.
Kaffir-Lemongrass Panna Cotta
1 cup whole milk
1/2 cup sugar
zest of one lemon, and one lime
10 kaffir lime leaves
1 stalk lemongrass, bruised and chopped fine
1 tbsp chamomile buds
3 cups cream, 1/2 cup held very cold
4 sheets gelatin
Place 1/2 cup of cream in the bowl you intend to whip it in, and place it in the refrigerator along with the whisk you intend to whisk it with.
Gather six 6-oz serving dishes or desired molds
1. Steep the milk with the sugar and flavors. Place the milk, sugar, lemon and lime zest, kaffir leaves, lemongrass, and chamomile in a small sauce pan and heat just below boiling, stirring to dissolve the sugar. Remove from heat and steep for half an hour. During the last 5 minutes, soak the gelatin sheets in ice water.
2. Add the gelatin. Strain the milk, and return to a sauce pan, rewarming the milk. Remove the softened gelatin sheets from the ice water, squeezing to remove as much of the water as possible. Add the gelatin to the warm milk, and stir until completely dissolved and evenly dispersed. Transfer to a bowl and allow to cool on the counter at room temperature for 1 hour.
3. Whip the cream. When the milk is cooled, begin whipping the 1/2 cup of very cold cream. Do this with gentle back and forth motions of the whisk, avoiding beating much air into the cream. You should see the cream begin to thicken in a minute or two, once the fat globules are damaged enough to adhere to each other. Continue gently agitating the cream with the whisk, stopping when the cream is thick enough to hold itself, but doesn’t quite hold peaks.
4. Add the cream to the cooled milk/gelatin. Add the unwhipped cream to the milk/gelatin mixture that has cooled on the counter with a whisk. Carefully now, add the whisk thickened cream and fold with a spatula until the two are evenly combined.
5. Fill the molds or serving dishes. Pour the panna cotta into the dishes or molds quickly, as the cold from the cream will now begin to fully set the gelatin. You will see the mixture is thick, and may need to tap the glasses a bit to obtain a flat top, or use an offset spatula to smooth the top of the molds.
6. Chill the Panna Cotta. Place the panna cotta in the refrigerator and allow to set overnight. It will take a full day of setting to achieve the propper texture.