Modern mixing chambers operate under vacuum to minimize oxidation of the pigments and loss of the yellow color. Next, the dough is extruded through various shaped dies, under very high pressures, to produce the wide range of different shapes of pasta products. The extrusion chamber is temperature controlled, usually at about 50C, to dissipate heat generated by the pressure and friction created during the extrusion process. Temperatures in excess of 50C can damage the semolina gluten proteins and reduce pasta quality. Lastly, the product is dried.
Long pasta is subjected to a blast of air, immediately after extrusion, to minimize stickiness.
Short pasta is transferred to a shaking pre-dryer to prevent it from sticking together. Generally, the product is dried to a moisture of about 12 per cent using different drying regimes. Drying is a very crucial part in the production of high quality pasta products. Temperature and humidity in the drying chambers are controlled so that water is slowly evaporated from the pasta. If dried too slowly, the pasta may develop a sour taste and if dried too fast, the pasta becomes brittle and breaks easily.