Recommended application of fermentation methods

The method chosen from the options provided above should be appropriate to both the quantities of wet bean available as well as the objectives of the study. 

The Styro-cooler method is used for homogenous or defined bean masses and takes more beans than the batch insert micro fermentation method. The batch insert micro fermentation allows more samples to be processed but requires larger fermentation masses (mother heaps/boxes) to insert the mesh bags into. 

There is also the potential risk of some flavour transfer from the larger fermentation mass. Single pod micro fermentations handle small quantities without contamination but suffer from the lack of averaging a larger number of pods. Each method used therefore has advantages and disadvantages which must be considered and weighed against the benefits derived from using a particular method.

Drying

The beans should be carefully and thoroughly dried. Further guidance on best drying practices is provided in Part III Section 3bt. Where the batch insert micro fermentation method has been used, the samples can be dried in their mesh bags though care should be taken that the beans are not spread in a one bean thick layer on a drying tray, since this would result in drying at too fast a rate due to full exposure of all beans both to air as well as to the sun. 

Samples from Styrofoam container fermentations should be dried in small heaps. All samples, including those in mesh bags, should be heaped up at night in a tempering phase to allow moisture to migrate from inside the bean to the surface.

It is essential that when many samples are being prepared at the same time (such as with multiple batch insert micro fermentations) they are not mixed up during drying and trays with individual labelled cells or separations can be used to minimise this risk.

The optimal end point of drying should be between 6.5 – 8% moisture content as assessed by a suitably calibrated moisture meter.