| When using simple distillation equipment it is important to ‘remove solids` after fermentation and before distillation otherwise distilled alcohol quality will be poor.
During distillation the fermented liquid is heated to ‘boil off` the alcohol – if yeast cells and other solids are allowed into the distillation stage the heating process will rupture cells releasing unwanted off flavour and aroma into the distillation process. Simple distillation/rectification equipment will not be able to separate out such unwanted impurities and these will be carried across into your distilled alcohol reducing quality.
Removal of solids after fermentation is even more important where DISTOSORB is used in fermentation. DISTOSORB continually absorbs unwanted impurities throughout the fermentation, trapping these compounds within its pore and surface structures. These impurities will be released during the boil if clearing agents are not used to remove solids at the end of fermentation.
In 1993, SPL invented a new high performance clearing system based on two components 'silica sol' a negatively charged 30% colloidal silica solution and 'chitosan' a positively charged macro molecule. At the end of fermentation yeast cells will ‘sense` the low level of sugar and grows filaments from the cell surface (hair-like protrusions) to allow yeast cells to group together, flocculate and drop out of the ‘poisonous` alcohol solution for yeast survival. Adding clearing agents helps speed this flocculation process by ‘seeding` the fermented liquid evenly with negatively charged silica particles followed by addition of positively charged chitosan. One hour later – the large chitosan macromolecule will envelope yeast cells and other solids forming strong local bonding with negatively charged silica sol particles producing a tight floc which rapidly drops to the bottom of the fermenter.
This silica sol/chitosan clarification system outperforms traditionally used clearing agents such as gelatine, isinglass, egg albumin and other products by at least a factor of 10 causing solids to drop out of fermented liquid at a rate as fast as 1 metre per hour leaving bright/clear fermented liquid above. Traditional clearing agents can take many weeks to produce a similar degree of clarity.