Botanicals used in making gin are instrumental to its flavor. Juniper berries, coriander seeds and caraway seeds used in London dry gin styles such as London Dry G&T can be steeped in neutral spirit prior to being combined with other ingredients for distillation, which allows their full potential flavors to come through. Other botanicals like fennel and black pepper require more delicate handling – for optimal extraction use an alternative method like steeping or boiling to bring out their full potential.
One popular approach is known as the ‘steep and boil” method, in which botanicals such as juniper are steeped into neutral spirit that has been diluted down to about 50 % alcohol by volume using spring or purified water, followed by repeated distillations (rectification) to strengthen and refine flavor before being further reduced with water to bottling strength.
Distillation occurs repeatedly with the same base, yet each iteration will produce something unique as oils extracted from botanicals will vaporise at different rates; citrus botanicals tend to come off first while wax residues leave their mark later – therefore distillers must sample to understand when to switch into the “heart” of their distillate (which eventually will form the basis for gin). Some producers like Hendrick’s employ a reflux column instead, slowing the speed of alcohol vapour flowing through their baskets so that botanicals can impart more subtle flavours into their products.