coffe addict wrote:Because packed sections have a higher theoretical plates per metre ratio. Simply put they are more efficient at producing neutral.
Debatable on both statements. Year sure 1.5 metres of packing is more than 600 mm but that doesn't take into account what the plates are delivering to the packed section. The vapour is being delivered to the packing already highly rectified and depending on the amount of plates V coolant V vapour speed it might be somewhere close to azeotropic so all the packing is required to do it strip what little flavour is left and raise the ABV by a % or to which say 500 or 600mm is a lot more than capable of. The biggest difference between a bitey and clean crisp smooth result from say a TPW is often the result of prestripping either with a pot or a column with the deflag shut off (which is in fact a pot still) . There is nothing wrong with a reflux still but to get a good result in a single run does mean a slow arsed run, pre-stripping will also speed up those runs but it still won't approach plated column speeds. Filtering is another way to clean the spirit up but again this it time and expense most would prefer to avoid.