Chefs who are passionate about molecular gastronomy adore
innovating and experimenting. The modern cook’s hardware is
constantly expanding and culinary techniques are continually
improving and being reinvented. Gelling, spherification and
emulsification are the flagship techniques in molecular gastronomy.
However, many other techniques are also used.
Siphon whipping differs from emulsification in that foams can be
made without using an emulsifying agent. The product resulting
from siphon whipping is usually called espuma, derived from the
Spanish word for “foam”.
The culinary whipper has been used for a long time to make
Chantilly cream, also known as whipped cream. To do this, the
cream is first poured into the siphon. Then an oxide nitrous (N2O)
cartridge is inserted into the device, which releases its gas inside
the bottle. Pressurized gas bubbles then penetrate the fatty liquid.
This is why the cream’s volume increases once the liquid has been
ejected from the siphon. It is worth noting that the volume obtained
is much greater than that achieved when using a whisk to make
Many espumas are made using liquid ingredients to which cream is
added. Creams and other high-fat materials are always beneficial
additions to espumas since fat molecules facilitate the dissolving of
gas in the preparation. Solid ingredients can also be used, as long
as the preparation is filtered before being transformed with the food
siphon. Simply transform solid foods by cooking, then pureeing and
extracting the juice using a fine sieve. Even very small particles may
obstruct or clog the food siphon while it is pressurized.
Finally, emulsifiers or gelling agents can be substituted for cream
fat. Additives such as gelatin, agar-agar or xanthan gum can help
stabilize any kind of espuma – some may even be served hot! As
with all recipes requiring hydrocolloids, we recommend letting
the preparation settle a bit while the gas is pressurized in order
to allow the molecules to hydrate. A settling period of 20 minutes
inside the food siphon yields a much higher volume of an espuma
compared with one in which the hydrocolloid does not have the
time to properly hydrate.
SUSPENSION AND THICKENING
Thickening is not a new or spectacular culinary technique, but some
thickening agents borrowed from the food processing industry
are increasingly used in creative cuisine to add a slight touch of
extravagance to dishes and cocktails! Without a doubt, xanthan gum
is an additive that is becoming increasingly popular.
Due to its ability to replicate a creamy texture, xanthan gum is
often used as a fat replacement in preparations. This creaminess is
created by the bonds that join between the gum molecules, which
form a network that traps air in the liquid preparation.
This same property is also used in molecular mixology whereby
xanthan gum is added to cocktails to create a suspension effect.
You can thus “suspend” fruit, herbs or flavor caviar in a liquid.
Another technique used in some recipes in this book is the
transformation of liquids with high fat content into a fine powder. The
additive that makes this technique possible is called maltodextrin
and is derived from tapioca sugar, which comes in the form of a
very low density powder.
The transformation into powder is a very straightforward process:
simply add maltodextrin powder to a high-fat preparation and blend
until you get the desired powdery texture. The solid ingredients
must first be liquefied and it may be necessary to pass the powder
through a sieve to remove any lumps.
So it’s easy to add an entirely new dimension to dishes with a powder
made from olive oil, chocolate, peanut butter or even bacon! By
reducing the proportions of maltodextrin in the mixture, it is also
possible to create flavored “lumps” that can be caramelized and
crisped on the outside.
Liquid nitrogen has long been used in molecular gastronomy
demonstrations and the instantaneous vapor cloud that results
from the condensation of ambient air is very impressive.
However, besides its “wow” effect, there’s another reason for this
technique’s enduring popularity. Due to its ability to quickly cool
preparations, liquid nitrogen significantly outperforms the classic
freezing process. Freezing at -4°F (-20°C) causes water to form
into increasingly larger crystals and alters the product’s initial
structure. Frozen products thus lose a lot of their water and soften.
The radical change in temperature brought about by nitrogen
ensures the formation of much smaller ice crystals that leave the
product’s cell structure intact.
In cooking, liquid nitrogen is used as a coolant. It is not an ingredient
and so it is never ingested; it cools the food, then evaporates. The food
can be ingested only after the liquid nitrogen has fully evaporated.
Foods that have been cooled with liquid nitrogen are extremely
cold, as they have been in contact with this cryogenic substance,
and should be left to warm up before being touched and ingested,
in the same way that foods dipped in boiling oil must cool down
before being touched. The denser the food, the colder it will be and
therefore the longer it will need to warm up. This is why chefs usually
dip low density confections, such as meringues or frozen mousse,
into liquid nitrogen.
Some chefs use the cooling properties of liquid nitrogen to make
extremely smooth ice cream. The creaminess of the ice cream is
obtained due to the small size of the ice crystals formed during
cooling with liquid nitrogen. Liquid nitrogen makes it possible to
freeze alcohol to make original cocktails, which is not possible with
traditional freezing techniques. It is also possible to create flavor
powders using ingredients such as fruit or flowers that have been
crushed when frozen.
However, the extreme cold of liquid nitrogen makes handling very
dangerous. We recommend that you take training to understand
the reactivity and risk of burns.