04 April 2012

A Look into the Gastrovac

I should preface this with the statement "this is not cheap" it is one of those pieces of equipment you really have to use regularly and in practical ways to get your moneys worth. That being said if it is used in the correct manner, as an investment, it is a sound one.

A big part of the attraction a Gastrovac holds is it's sheer diversity. It can be used to sous vide, vacuum, cook, to infuse, and fry all in one machine. It was designed and built by Torres ad Javier Andres of La Sucursal restaurant in Valencia, who teamed with a group of scientists from Valencia's Polytechnic University. What set these two chefs apart was there approach. They said that while other chefs were trying to make one food taste like another they were trying to make food taste more like itself, bringing out it's natural deliciousness.

Another notable advantage, especially for the drinks world, is the sheer volume of liquid the Gastrovac can hold up to 8litres in its pot at one time.

It is dubbed "a compact appliance for cooking and impregnating in a vacuum." The official stance on how it works is…. " by creating an artificial low pressure, oxygen-free atmosphere, the gastrovac considerably reduces cooking and frying temperatures, maintaining the texture, colour and nutrients of the food. Moreover, the Gastrovac creates the sponge effect: when the atmospheric pressure is restored, the food absorbs the liquid around it, allowing infinite combination of food and flavours." So it is not just for making food taste more like itself, you can infact make a pineapple taste like a cherry, an apple taste like chocolate and so on....

There seems to be a key theme running amongst everyone who owns a Gastrovac. They stress the importance of experimenting with the machine. Luckily several years on since its release there is a lot more information published so you won't be starting entirely from scratch.

In more easily understood English the Gastrovac cooks under vacuum conditions using the temperature control of induction. Similar to a rotavapor it means you can boil water at 40c or fry oil at 80c. This has two effects. One, you can retain nutrients in food because the temperature is lower meaning more flavour. Secondly, you can cook more delicate products such as flowers who's volatiles would be burnt away and flavour lost at normal temperatures.

Now, despite the sheers and unbridled joy that comes from eating something boiled at 40c. the Gastrovac is becoming better known for its "sponge effect". You can achieve the same effect within a Vacuum machine, however the Gastrovac has the advantage of allowing you to cook at the same time.

Simply explained the sponge effect happens when the pressure in a vacuum is returned to normal. The liquid within the Gastrovac will rush into and be absorbed by the food infusing and flavouring it.

One school of thought states that you can cook chicken in broth, with bones, herbs, etc then return the vacuum to normal. The chicken will absorb all of the flavour surrounding it, creating, what I am assured, is a taste experience like no other.

On the other hand, one example cites adding fruit to a wine broth or sweet sauce, then returning the vacuum to normal creating fruit infused with the sauce or wine.

One idea follows the initial train of thought for the machine, i.e making food taste more like itself whilst the other takes a more "modernistic" aproach, and makes food taste more like other food.

While ideas may still be slightly sparsely dispersed throughout the internet the kind people at Chefs Tools have these to share....

Strawberries keep their shape and consistency at 45c for 20 minutes. Depressure 10 times throughout the 20 minutes when cooked with any jus syrup or wine to infuse flavour.

Pineapple's cooked at 55c for 45 minutes creates an almost transparent product when cooked with any jus, syrup or wine.

Impregnating chicken instead of marinating for 2 days. Place the chicken, plus marinade into the gastrovac. Set to an ambient temperature and depressurise every so often to drive the marinade into the chicken. Sounds a bit like chicken infused with chicken.....

As we mentioned, half the fun of a Gastrovac is experimenting. That being said we are still well within the experimentation process, however expect some finalised and official Drink Factory recipes to be released in the future.

1 comment:

Tony Harion said...

I can vouch for the effects of the gastrovac, but I’m not 100% sure about the investment.

I admit not having a chance to fully explore one for a long period of time, but I think we have achieved somewhat similar effects using things that cost almost nothing (if you have a sous vide bath and a cheap oil based vacuum pump).

I might be wrong here, as I said I haven’t played with the actual machine very long.

We have been using jars with connectors adapted to the lid (or valves) for quite a while and we´re pretty happy with the results for bar use.

The volume of the gastrovac is a bit bigger, but a larger pot with an acrylic lid might to the trick.

You can check some pics of the setup we use to “replace” a gastrovac here: http://on.fb.me/Cookingissues

(we created the album for a question to Dave´s radio show, that’s the reason for the name)

Comments are very welcome.