Sous Vide meat

When temperature rises during cooking, meat suffers a number of changes at chemical level, predominantly protein denaturalization and colagen solubilization. The later becomes in gelatin.

Theses changes can be described as follow:
Protein denaturalization produces a shrinkage of myofibrills, first transversally (between 40 and 60 Celsius), and then longitudinally (above 60 Celsius) which reduces water holding capacity resulting in a harder and less juicy meat.

Protein denaturalization can be described in step according to the involved proten:
- Sarcoplasmatic proteins denaturalize between 40 and 60 Celsius
- Myosin denaturalizes between 55 and 60 Celsius
- Myoglobine, which is responsible of red color, denaturalizes above 60 Celsius
- Actin denaturalizes above 80 Celsius

Colagen wraps muscular fibres and is responsable of toughness. When it solubilizes is called gelatin and meat becomes more tender.

- Colagen solubilization starts at 60-62 Celsius, and it is evident above 65 Celsius

Collagen solubilization is a slow process while water capacity loss is very small in Sous Vide. For theses reasons, Sous Vide produces tender and juicy meats even from tough pieces.
In valuable pieces of meat like tenderloin, the results are not as spectacular as the results with other meat pieces like T-bone steak or ossobucco.

In resume, we can say that meat starts to cook at 40 Celsius. Different doneness are between 50 and 65 Celsius. Rosè doneness can be done only below 60 Celsius. Over 80 Celsius, meat is overcooked.
Colagen-rich pieces have to be cooked for a long time above 60 Celsius to solubilizate colagen and become tender.

Animal specie, piece size an final doneness define the right time and temperature (see tables)

Food safety in Sous Vide meat

At working temperatura, between 50 and 65 Celsius, bacterias in meat die but their spores do not. These spores can germinate and reproduce if the food is kept at a risky temperature, resulting in a food poisoning episode, sometimes serious.

To avoid it, the piece of meat have to be either eaten inmediatedly (cook and serve) or chilled rapidly (cook and chill) until the core reachs a temperature of 2-4 Celsius. Upon chilled, it can be either storaged in refrigerator or frozen.
Frozen pieces can be thawn in Sous Vide Supreme at 45 Celsius and served in a pre-heated plate.

In no case, refrigerated food can be storaged longer than one week. Never ever!

Cooking time depends on piece size, thus we do not say specific data in this general description.
You can find specific data in recipe books or in the net.