Normal, silver, and gold quality items can be prematurely removed from a cask at any time by striking the cask with an Axe, Hoe, or Pickaxe.
Casks are able to produce items with "iridium star" quality. Iridium star is the highest level of quality, which doubles the value of an item. Different types of items take longer or slower to age. Wine takes the longest -- 2 seasons of aging to go from basic wine to iridium quality wine.
Casks can be placed anywhere, however they will only accept goods to refine if they are actually in the cellar.
It's worth noting that even with high-value goods such as Starfruit wine, the value gained from casks is comparatively low, since an iridium-quality product is only double the original value. Maturing a bottle of starfruit wine will yield 2250g in 56 days, yielding only 40g per day per cask. That is very low maintenance profit, however. You only need to fill the cellar and wait for two seasons. With starfruit wine, 125 casks will yield 5000g per day.
The cellar comes with 33 casks. It's possible to fill the cellar with 125 casks and still leave paths to reach all of them without displacing any of them.
It's also possible to completely fill the cellar with Casks. This requires 189 casks, made of 156 Hardwood and 3120 Wood. In order to use all 189 casks, the player must fill the casks all at once, placing additional casks while moving towards the exit. In order to harvest the finished product the player must reverse the process, removing empty casks while carving a path to the furthest ones. This can be time-consuming, so it may be a desirable option for only the most valuable products (e.g., Starfruit or Ancient Fruit wine).
All layouts described here are shown in the Gallery below.
Note that players using a controller or playing on mobile devices, rather than using a mouse/keyboard, have reported difficulty accessing casks in the corners of the Cellar.
Followed by all other wines in descending order of fruit/wine price.
Note that although large milk/large goat milk make gold quality cheeses directly, the final aging step gold quality to iridium quality is both 50% of the total value increase and 50% of the required time, so the g/day is the same for that step as it is for the process as a whole. The prices above are with no skills: Artisan raises both the base prices of cheeses and alcoholic drinks by the same percentage, so it just increases overall profits, but the relative order of cask-aged products' g/day stays the same. Choosing Rancher, however, will only increase the prices of the cheeses, raising Cheese to ~19.7 g/day and Goat Cheese to ~34.3 g/day, now slightly better than Ancient Fruit Wine instead of slightly worse, but not a major of change.