Making bread is equal parts art and science. A lot of the skill involved in making great bread is knowing how long to leave the dough to rise. This stage is called proofing, and it helps the dough to develop flavour and increase in size before baking. Different types of bread need to prove for different lengths of time, and this used to mean bakers had to start working extremely early in the morning.
Luckily modern technology provides enormous control over these processes. This is partly due to understanding how yeast is affected by temperature. While there are some differences in strains, most will die above 57°C, but will enter a state of dormancy at around 4°C. Retarding the dough by storing it at 4°C frees bakers from the need to immediately begin baking it, and allows them to prepare batches of dough to be ready for the following morning, or even after the weekend.
As you can imagine, the specific conditions required to keep the retarded dough in peak condition make standard refrigeration unsuitable. Specialised equipment like Williams’ Crystal retarder prover cabinets use advanced control systems that can keep the dough retarded before automatically starting the proving process so it’s ready at a predetermined time.
These cabinets aren’t simply refrigerators, the proving phase gently warms the dough using ‘intelligent’ steam generation and they control the balance of temperature and humidity during both the retarding and proving processes. The steam helps to keep the skin of the dough moist, which helps to create a crust during baking.
The demand for artisan breads has increased hugely in recent years, along with different bread types designed to meet special dietary requirements. These may use different kinds of flour or use alternative leavening agents.
For example, Sourdough uses lactobacilli, which requires a lower temperature range than yeast to prove. Retarder/provers are vital for making a lot of artisanal breads, not just sourdough.
While speed is the main factor in industrialised bread production using the Chorleywood process, artisan breads are far better served with longer fermentation periods. Equipment like Crystal retarder provers can help bakers diversify their range without having to give up too much free time.