Why do our choux buns collapse during baking

It is important when baking choux products that the oven temperature is sufficiently high to impart heat quickly at the start of baking. Consequently a rapid recovery of the baking temperature after the product has been loaded into the oven is vital. If the temperature controls are set too low then the recovery rate is low, resulting in shrinkage or collapse of the products. If the steam damper is partly or totally open the problem is exacerbated. The best results are obtained when the steam damper is closed (no loss of heat) and the baking temperature is set as near 232 °C (450 °F) as possible.

12.7 We stand our finished choux buns on U-shaped cardboard and wrap them in a cellulose-based film. Recently we have observed the growth of mould colonies on the products. Why is this?

In general choux products with fillings are susceptible to mould growth, and if the products are wrapped, the danger of mould is increased because of the greater degree of moisture maintained around the choux buns by the cellulose wrapper. The cardboard on which you hold the products will absorb water from the product because of both gravity and moisture migration. It is important that good hygiene practices are observed not only in the production process but also in the storage of the U-shaped cardboard and the cellulose wrapping film. Both cardboard and wrapping film should be stored covered in a clean dry place.

From the hygiene point of view the surface of the choux products should be cool and dry before filling and coating. They should be kept covered while cooling and drying-off to prevent mould spores settling on them. If the goods are cut to insert the filling, keep the cutting knife free from mould spores by regularly wiping with either a 12% acetic acid solution diluted in water (for stainless steel knives only) or industrial (not household) methylated spirits diluted in an equal quantity of water, or hydrogen peroxide. Care should be taken when handling acetic acid or hydrogen peroxide. Where products are filled by injection through a nozzle then the nozzle should be wiped at regular intervals with solutions similar to those mentioned above. The products should be handled as little as possible to minimise contamination. Clean and wash benches and trays that are to be used.

Use of a semi-moisture-proof cellulose film will allow more moisture to 'escape' from the atmosphere surrounding the product and keep the humidity within the packing material at a lower level. Waxed or coated card will prevent moisture from being absorbed into the cardboard and supplying a source of water for mould growth.

If the water activities of the choux pastry and its filling are manipulated to bring their values closer there will be less likelihood of moisture migrating through and out of the product. If the water activity of the filling can be lowered towards that of the choux, there will be less mould growth because of the overall lowering of water activity in the composite product.

Continue reading here: We find that our Viennese fingers go soft very quickly after baking How can we prevent this from happening

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  • angelico
    Why shoux buns collapse after baking?
    5 months ago
  • Cari Harrison
    Why does choux pastry collapase after baking?
    6 months ago
    Why did my choux buns collapse?
    8 years ago