Stockpiles are single-use consumables that provide a lump sum of either Food, Industry, or Science. The base Food Stockpile, Industry Stockpile, and Science Stockpile each provide 100 of their respective resource, but this can be increased via the Unskilled Labor and Organized Labor technologies in Era III and IV respectively. In addition, the Necrophages or any custom faction with the Recycling faction trait are able to produce Recycled Stockpiles, which are a separate kind of Food stockpile gained from units falling in battle.
Stockpiles can be used via the Empire Management Screen, appearing directly below Luxury Resources. To use a stockpile, simply click on the stockpile you wish to use, and if it's a Food or Industry stockpile, select the city you want to apply it to. However, the effects of stockpiles do not directly stack; using multiple Science stockpiles in one turn, or applying multiple Food or Industry stockpiles to a city in one turn, will not increase the amount of resources received that turn, but will instead make it so that the effects of the respective stockpile is applied to the city or empire for a number of turns equal to the number of stockpiles used, e.g. using three Science Stockpiles in one turn will result in getting +100 on empire for the next three turns. You can, however, get the benefits of a Food Stockpile and a Recycled Stockpile on the same turn.
There are several methods to gain stockpiles, each with their own benefits and drawbacks.
- Marketplace: Stockpiles can be purchased from the Marketplace in the Stockpiles section once the Imperial Coinage technology has been unlocked from Era II.
- Unskilled Labor: Once the Unskilled Labor technology from Era III has been unlocked, you can initiate the repeatable Smokehouse, Warehouse, and Royal Academy construction projects in your cities, which will grant you one Food, Industry, or Science Stockpile respectively upon completion. Unskilled Labor will also increase the resource quantity of stockpiles by 500.
- Organized Labor: Once the Organized Labor technology from Era IV has been unlocked, you can initiate the repeatable Cannery, Industrial Zone, and Royal University construction projects in your cities, which will grant you one Food, Industry, or Science Stockpile respectively upon completion. These constructions will override those unlocked by Unskilled Labor. Organized Labor will also increase the resource quantity of stockpiles by 1000.
- Diplomacy: You can trade stockpiles with other empires, offering something in exchange for their stockpiles, but your ability to do this is limited by your diplomatic status with the Empire you are negotiating with. The conditions are as follows:
- War: You must be proposing a truce treaty.
- Cold War: You must be proposing an alliance or peace treaty.
- Peace: You must be proposing an alliance treaty, commercial agreement, or research agreement.
- Alliance: You must be proposing a commercial or research agreement.
- Recycling Trait: The Necrophages have the ability to produce Recycled Stockpiles. Recycled Stockpiles provide 120 Food to a city, but this amount is not increased by the effects of Unskilled Labor or Organized Labor. One Recycled Stockpile is gained for every 8 units killed in battle - both yours and the enemy's - so long as the battle does not end in defeat.
- Weapons of the Enemy Trait: A faction with the Weapons of the Enemy trait, such as the Cultists, immediately razes any city it captures and gains 1 Industry Stockpile per Population when the city is razed. For example, if a faction with this trait conquers a city with 5 population, the city will be razed and the conquering faction will be given 5 Industry Stockpiles.
- This trait can be further enhanced with the Cultists' Era II Destructive Analysis technology, which grants 1 Science Stockpile per Population when a city is razed.
- Pearl Hoarding Blessing: After the first winter and constructing the Altar of Auriga, the Pearl Hoarding Blessing can be unlocked for 10 Pearls. This blessing unlocks the repeatable Pearls of Plenty, Pearls of Production, and Pearls of Wisdom construction projects in your cities, which will grand you one Food, Industry, and Science Stockpile respectively upon completion. While these construction projects require less Industry to produce than those unlocked by Unskilled Labor and Organized Labor, they have an additional cost of 8 Pearls.
- Due to the relative scarcity of Pearls, the number of other unique projects that require pearls, and the variety of other ways to gain stockpiles, it is generally not recommended to unlock this blessing, as the Pearls can usually be put to better use elsewhere.
- Oceanic Facilities: The Food Stockpile Facility, Industry Stockpile Facility, and Science Stockpile Facility each produce one of their respective stockpiles every ten turns, which will be granted to the empire in control of the fortress the facility is attached to.
- Siege Engineering: The Kapaku have access to the Siege Engineering technology, which grants Rubble Stockpiles for dealing fortification damage to cities.
Strategically, stockpiles are an inefficient way of creating the given quantities, but they are often deployed to put something useful in the queue of a strong industrial city that has built most everything of practical use yet made available by way of techs. They can be useful if you intend to settle new city mid to late game and want it to hasten it's growth or military or building development without using dust. A stockpile is simply a conversion of industry to a transferable resource, much like dust can be 'converted' into industry across the empire through buyouts. Note that Era IV buildables, though just over twice as costly in , are much more efficient than those of Era III, providing almost 3 times the transferable , or . Also note that the prices of stockpiles on the market do not change, making buying them generally a very efficient investment of dust if you have the Era IV buildables unlocked.
However, one of the most effective ways to use Stockpiles is by creating or acquiring a large amount of them before researching Unskilled Labor and/or Organized Labor; because the value of all stockpiles you have increases upon unlocking these technologies, it is possible to collect a large amount of low-value stockpiles that would otherwise only produce 100 of a given resource relatively cheaply, and then suddenly have their value jump up to 1600. The most common way to do this is with Pearl Hoarding (especially for the Allayi, Cultists, and Mykara) or by researching Unskilled Labor and creating a lot of stockpiles before researching Organized Labor.