The Whisky making process if full of nuance and language, but here I try and break it down into a few short paragraphs. I have detailed the process of Scotch Malt Whisky, other whiskies might start out with different cereals (grain, corn, rye) and might have some specialised steps, but generally, all Whisky is made the same.
Malt is steeped in water to allow it to germinate, this process starts the conversion of starch into sugar. To conclude the germination, the maker will dry the malt over hot air (this does not add any flavour) or over hot peat smoke. Peating adds oils (phenols) to the barley which provides great big smokey flavours.
The malt is then milled into a coarse flour called grist.The grist is added to a huge container called the Mash Tun alongside hot water. This mixture has now become the 'worts' and is drawn down from the bottom of the mash tun. The worts are cooled, yeast is added and fermentation is now ready to occur in a vessel called the Washback. The fermentation process is obviously of great importance, a short fermentation of less than 48 hours will produce a malty final spirit. Longer fermentations of over 55 hours produce lighter and fruitier flavours.
The product of fermentation, called the Wash, is now distilled twice (or thrice at some distilleries). Distilleries use copper stills, these impart flavours to the spirirt depending on the length of time the spirit is in contact with the copper. The longer the 'conversation' between spirit and copper the lighter the flavours imparted. The alcoholic vapour from the stills is cooled in a condensing system.
The distillate is now termed the 'New Make'. It is diluted down to 63.5% alcohol and is ready for maturation in oak casks. Now the Whisky maker has to make a decision on the casks. Traditionally the maker opts for Sherry or Bourbon casks (though other funkier options are sometimes seen, ex-wine or ex-port casks). Sherry casks (previously used to age sherry) are made from European oak which imparts dark, fruity flavours, clove, nuts and incense. Bourbon casks are made from American oak and impart pine and vanilla elements, some spice and coconut.
Now all is left is to let the New Make age for a minimum of 3 years and, voila, you have yourself a Malt Whisky. Cheers!