Vacuum cooking is not a
new concept by any means but searching online for professional
documentation always sent me towards the industrial sector with
experimentations on fresh meats or fish. As my primary sector is
retail I have tried to adapt the newly discovered techniques to a
more artisan fashion.
Vacuum cooking brings
some advantages that would not be possible with other techniques like
the possibility to cook contemporaneously different type of foods, we
can cook beef meat and fish at the same time with bought any flavour
contamination whatsoever.
Vacuum sealing, as we
all know, is not a cooking method nor a preservation one. It is a
packaging method. With this in mind vacuum packaging is indispensable
to the retailer or the hospitality sector operator. For example it
increases shelf-life, flavours and colours are preserved and it can
even make meats more tender by modifying the glycogen present in
them.
Ingredients.
For vacuum cooking a
modern retail kitchen should have a steam capable oven , a vacuum
sealing machine and a blast chiller wich is mandatory for good
results with the vacuum cooking. The nice thing about this cooking
technique is that it transforms a simple packaging method in a
preservation one but for this we need to follow some basic rules in
the production chain. First of all is hygiene as the possible
contamination of foods before their sealing will compromise their
shelf-life. Another factor to keep in mind is the time that foods
will be outside of the fridge before the actual cooking is started
and anyway that should occur at a inferior to 10°C room temperature.Ussage
The correct usage of the
oven is the key factor of our success and although it is a complex
mater here are some guidelines. Always use preheating with a chamber
temperature superior of 30°C over the cooking temperature for
products that are usually stored at 3°C or a chamber temperature of
“cooking temperature”+50°C for frozen foods. Using a temperature
probe during cooking is preferred to the “cooking time” approach.
One problem that I encountered with the temperature probe was that
the vacuum was lost even though we used some sort of sealing sponge
on the packages to be coked. As a backup solution I've used one non
sealed meat cut only for temperature probing, so if someone has some
better ideas please comment in the section below.
The blast chiller needs
a pre cooling stage too. Take into account that although we might
set a 3°C chamber temperature for the chiller , without a proper pre
cooling the temperature drop will last long over 90 minutes and that
is not desirable for good conservation.
The vacuum bags
That brings us to
consumables. There are allot of vacuum bag types but the one
appropriate for cooking will be PA/PP material at 80 micron
thickness. This material can resist temperatures 100 to 120°C and
can guarantee a 30 day shelf-life for refrigerated products.
Taste and flavour
When we think of cooking
we think of flavours, and flavour management with vacuum cooking can
be a tricky thing. One thing to consider is that the salt quantity to
be used per kilogram of product might vary with the way your clients
perceive flavours or by the type of product , vegetable , meat or
fish. There are some other problems related to salt and that is it's
purity from a microbiological point of view. The marine salt for
example can have a bacterial load that combined with the anaerobic
way of packaging will create that green liquid inside the bag wich is
nothing more than the biproduct of the metabolism of halophilic
bacteria. So keep an eye on your salt. Sugar is also used in
different percentages mainly because it balances the salt flavour and
helps preserving foods by absorbing water. It also helps preserving
the colour of fresh foods for a much longer time.
Depending of your needs
you can, for vegetables use 60 % salt 40% sugar then dosing that 20g
per kg of finished product. For red and white meats 65% salt 35 %
sugar with a dosage of 9 grams per kilogram. For fish use 65% salt
35% sugar with a dosage of 10 to 12 grams per kilogram of product.
Also spices along with
oils can be used to create marinades with the help of vacuum coking
helping in the creation of particular fragrances thus giving a longer
shelf life for the newly created aromatic oils. With fresh spices
use the vapour oven to cook them for 2 minutes at 100°C then vacuum
cook them together with olive oil for 30 minutes at 50°C.
Vacuum cooking , at
least for meats brings some hard to get otherwise advantages. One is
the fact that flavours will be evenly distributed inside the cooked
product thanks to the mechanical effect of the vacuum. Another one is
the fact that colours will be preserved much longer. This is
particularly convenient for restaurants for example , where large
batches of products can be cooked then used only when the client
requires them. The long cooking time combined with proper cooking
temperatures also provide a efficient way of destruction of any
latent bacterial load. Also during storage it will be difficult that
any contamination can occur. Vacuum coking will prevent excessive
weight loss. My personal experience was that cooking in a traditional
way 1 kg of frozen prawn tails will result in a weight loss of 50 to
55%. Vacuum cooking will reduce that to a loss of about 40% always
thanks to the mechanical action of the vacuum which will prevent water
escaping the product mass. This has also demonstrated to be true for
beef and vegetables.
One side effect of the
mechanical action of the vacuum is the fact that flavours are more
intense than traditional cooking. Just think about of the dilution
and lost of juice from a traditionally boiled product compared to the
closed ambient of a vacuum bag. So keep in mind this factor when
using spices or additives.
Although anyone should get temperatures through experimentation and there are allot
of factors that influence cooking like the oven performance , quality
of meats, correct reading of product and chamber temperatures etc.
below there is a list of vacuum coking temperatures:
- 50°C oven chamber temp.(C.T.) - avoid this as it is dangerous from a bacterial proliferation point of view
- 60°C C.T. and 54°C product temp.(P.T.) for roast beef with raw interior
- 60°C C.T and 58°C P.T. for cooked beef
- 68°C C.T. and 66°C P.T. for well cooked beef and pork
- 75°C C.T. and 72°C P.T. for well coked chicken, beef or boned pork
- 85°C C.T. highest cooking temperature based on the quality of your cooking bags
Reheating of cooked products.
Reheating of the already
cooked products is almost mandatory at least for the hospitality
sector operators. It can be done in 2 ways : using the steam oven and
keeping the product sealed in his vacuum bag or second alternative ,
opening the bag and cooking the product in a traditional way with the
instruments present in your kitchen. If your meat cuts are big the
first way can take a long time and you should keep that in mind.
Products reheated with
the first method can also be immersed in hot water at 65°C and kept
in stand by until further cooking is required, depending on your client requirements.
Generally there are some
rules to be followed when refrigerated products are served with the
reheating method and not only. For example foods to be served cold
should not stay outside of the 3°C temperature range for more then
30 minutes before they are consumed. The reheating process should
occur possibly just before foods are served. If they are not served ,
the reheated products are to be eliminated and anyway the reheating
process should not last longer then 30 to 40 minutes and the stand
by temperature should not be lower than 65°C.
I hope that this article
gave'd you some nice ideas on how to cook, preserve foods and how to
overall maximise gross profit for your business. For further info
don't hesitate to contact me.
Enjoy your meal.
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