Hi Tony. There are no stupid questions but some answers can be a little .. um .. dumb. I hope mine isn't. Here goes: when you rack the wine you are doing several things. For one thing, you are indeed taking the wine off the lees (the sediment) and much of that sediment is yeast, both live yeast that is yeast that tends to flocculate and drop out of solution and fall towards the bottom of the vessel and dead yeast. As time progresses and with the weight of the column of wine sitting on those dead cells what happens is the cell walls tend to collapse and the innards of those cells spill out. Some strains of yeast make good use of those innards but some strains don't and when they don't those decomposing innards at the bottom of your carboy can over time create off-flavors. Over time, they can produce off-flavors but short term, the yeast will feed off many of those compounds and those compounds contain a plethora of needed nutrients.And that helps your fermentation run smoothly So one reason to rack is to minimize the off flavors that the sediment can produce. But minutes after you have cleared up all the sediment more sediment drops out - again, much of that is yeast but some of that is tannin and fruit particles and pectins and a host of other compounds. So the second racking will remove the sediment that has formed subsequent to the first racking but the amount of lees at the second racking will be less. And here's the thing, each time you remove lees there will be less lees to remove the next time.. and the last time you rack is to prepare to bottle and at that racking what you want to be bottling is a wine with zero sediment because you really do not want to siphon any lees into a wine bottle. So you rack into a "bottling bucket or carboy so that your siphon has no lees to deal with and you can focus your attention on the business end of the siphon - the bottling wand. Do you need to rack? I would argue that if you are making a wine or a mead or cider and are bottling within a month or so then you only need to rack before bottling to help ensure sediment free wines in your bottles but if you are making a mead or a wine that needs to age for several months and you do not know whether the yeast you have selected works well with the lees then it is best to rack... and if you are making wines from a kit and you are not an experienced wine maker then I would strongly suggest that you follow the manufacturer's instructions. That way , should something not go right, you may be covered by their warranty. If you disregard their instructions any warranty is waived...
