There are four common types of bonded warehouses used for whisky casks: dunnage, racked, pallet, and rackhouse.
The size of dunnage warehouses means that casks cannot be stacked more than three high and are laid on their side; this ensures good air circulation and an even maturation.
The concrete floors and thin walls allow a seasonal change in temperature in a racked warehouse which results in slight variations in the volume of the whisky during the course of a year.
So much so that a Dundee based company released a product called "Scotch Bonnet" to sit on the top of the casks in an effort to reduce evaporation.
[8] Rackhouses are often very tall with metal roofs, and they are split into several floor levels each with up to three layers of casks.
The traditional structure of rackhouses is wooden timber which results in a warehouse that is very subject to external temperature changes.
Incredibly hot summers and cold winters cause expansion and contraction of the whisky, increasing the interaction with the wood of the cask and expediting maturation.
[10] A delivery order is a document signed by both the buyer and the seller of the cask and addressed to the warehouse keeper.
In the context of Excise Notice 196 a Revenue Trade is defined as: “anyone carrying on a trade or business concerned with the buying, selling, importation, exportation, dealing in, or handling of excise goods, and the financing or facilitation of any such transactions or activities.
Find a full definition in CEMA section 1.” If the new owner of the cask is not a revenue trader then they do not require a WOWGR – as per section 5.1 Excise Notice 196: “All owners of duty-suspended excise goods must get approval and registration, unless...the owner of the excise goods is not a revenue trader”[12] In 2021, numerous whisky magazines and newspapers began writing about the subject of delivery orders in relation to the potential for fraud and scams.