As I continue with my blog series on molecular gastronomy this week, I look at a technique that creates foams and froths. Culinary foams and froths that were known to only be found at fine restaurants twenty years ago are becoming a once again popular trend in dining these days and today’s chefs tend to go steps ahead of the basics. Some of the more common foams would be whipping creams, mousses or meringues. The better known froths would be best explained as the wispy types of foam, such as in a cappuccino or the head of a fine beer. These types of foams are basically enhanced by adding in gasses or air to increase volume and change the textures. With these types of foams and froths, the flavors are not generally changed or enhanced by this technique. Culinary foams and froths that were known to only be found at fine restaurants twenty years ago are becoming a once again popular trend in dining these days and tend to go steps ahead of the basics. There are multiple kitchen devices today that can be used for these techniques as I will discuss later in this blog.
Foams or froths are made simply by combining ingredients that are, or can be transformed into a liquid state and mixed with a gelling agent. The flavors can be anything from fruit juices to purees to even soup or stock bases. Once the flavor ingredient is chosen, it must be dense enough to hold its shape for a period of time. This is the reason for some type of thickener or gelling agent to be introduced. Lecithin or gelatin are two of the more common gelling agents, while fats found in dairy such as butter and cream also tend to work well. Foams that are created in this manner are generally known as fluid gel foams.
Originally these types of foams where whipped by hand or electric mixer to allow the air to incorporate. With the advances in kitchen equipment, one item has made it easier and is the preferred way to create a fluid gel or dense foam.is The device is known as a whipping siphon. A whipping siphon is a container similar to a can of whipping cream that you would find at any supermarket, with an additional section that allows the addition of NO2 cartridges. Unlike the can from the store where the gas is sealed within the can, a whipping siphon can be reused as often as needed. You would fill the canister with the chosen liquid and use the NO2 to pressurize it allowing you to create denser gel foams easily. If using gelatins for the gelling agent, the fluid should be refrigerated until it is set. When using this technique, the rule of thumb is that the thicker the fluid gel, the denser the foam will be.
A lighter more delicate foam or froth can be achieved using more common equipment such as an electric hand mixer or an immersion blender. By quickly blending the top of a liquids surface, a very light froth can be achieved. The gelling agents in the mixture will help allow it to keep its shape and not dissipate quickly as I discussed earlier in the blog. The recipe below demonstrates a simple yet creative way to utilize this technique.
Parmesan Air Froth
2 cups Grated Parmesan Cheese
2 cups Water
½ teaspoon Soy Lechithin
Over medium heat, bring the parmesan and water up to about 1750. Remove from heat and allow the mixture to steep for about 30 minutes. Strain mixture using fine cheesecloth and add the lechithin to the liquid. Mix at high speed with an immersion blender in a shallow bowl and collect the foams that surface. Place the collected foam in an air tight container with a lid and repeat the process as more foam will come to the surface. Freeze for about 12 hours for best results.
With today’s “foodies” and home cooks trying to deliver that wow factor in their own kitchens, you can see that this can be one of the easiest and most cost conscious techniques available. Something of this nature could definitely take Thursday nights spaghetti dinner up a few levels.