- "Double Tap, Double Tap, Double Tap, Double Tap, Double Tap, Double Tap, Root Beer. Root Beer. Who doesn't like the root beer?"
- — Edward Richtofen, after purchasing Double Tap Root Beer
Double Tap Root Beer is a Perk-a-Cola featured in Call of Duty: World at War, Call of Duty: Black Ops, Call of Duty: Black Ops II and Call of Duty: Black Ops III in the Zombies game mode. Double Tap increases the rate of fire (and effectively increasing recoil by the same amount, due to the weapons having less time to settle between shots) of all weapons by 33% and doubles bullet damage (2.0 version only). It also allows the player to lay down equipment such as Claymores faster and makes players operate bolt-action rifles, pump-action shotguns (as well as re-chambering them), and Wonder Weapons such as the Wrath of the Ancients noticeably quicker, as well as raising the firecap for semi-automatic weapons. It mirrors the effects of Double Tap.
Double Tap Root Beer costs 2000 points. It appears on every map except for Nacht der Untoten (World at War and Black Ops version), Dead Ops Arcade, Ascension (Black Ops version), and Bus Depot (Survival). The perk was first introduced in the map Verrückt.
The original Double Tap Root Beer is seen in World at War and Black Ops. It can be seen as a risky perk, as it increases the rate of fire and Bouncing Betty speed, however, many weapons have high rates of fire anyway. This effect is the most noticeable on weapons like submachine guns, which often have a high rate of fire. The effect is also amplified by the Pack-a-Punch Machine, as many of the upgraded weapons gain an increased rate of fire. This can cause ammo to deplete at an alarming rate if not used properly. On the other hand, the increased rate of fire lowers the time to kill, making it easier to kill a group of zombies. Double Tap Root Beer may not be helpful in the early rounds, when zombies have low health, but in the later rounds, it becomes very effective. It is often useful to have Speed Cola due to the fast depletion of a single magazine. For reasons stated above, on later rounds, it can become useful for players that have fast trigger-fingers and semi-automatic weapons like the M14 or the M1 Garand.
Introduced in Black Ops II is Double Tap Root Beer 2.0, an improved version of the original perk. In Black Ops II and Black Ops III, compared to its predecessor, Double Tap 2.0 is a very useful perk to have and considered essential to some. In addition to increasing rate of fire, it fires two for every round when a weapon is fired at the cost of one round (which can be observed when hip firing a sniper rifle), potentially doubling the damage assuming both bullets hit. This only applies to weapons using bullets; most Wonder Weapons and explosives are only given the rate of fire increase. If a player were to aim down sights and to fire a round, only one shot would be fired but it would have double the damage. This makes it better in nearly all circumstances to aim, as the shots will be twice as powerful. This perk is especially effective with players who equip weapons with high rates of fire, low damage and recoil, such as light machine guns and submachine guns.
For both Call of Duty: World at War and Call of Duty: Black Ops, the icon's color is dark goldenrod and shows two bullets flying through the air to the left. In Call of Duty: Black Ops II and Call of Duty: Black Ops III, however, the icon's color is orange and one bullet splitting into two separate bullets; this is to demonstrate its updated effect.
- Verrückt - Right next to the MP40 purchase on the German side.
- Shi No Numa - Will spawn randomly in one of the four huts.
- Der Riese - On the second floor of the automobile garage near the bridge.
- Kino der Toten - In the southern part of the alleyway next to a barrier.
- "Five" - In the War Room next to the first elevator.
- Call of the Dead - Located on the deck on the right after getting on the boat.
- Shangri-La - Will spawn randomly in the mines (changes spawn with Deadshot Daiquiri, PhD Flopper, and Stamin-Up).
- Moon - Located on the first floor of the laboratories.
- Nuketown Zombies - Spawns randomly along with the other perks every five rounds (starting on 1, with the exception of solo, then 5, then 10) on stacks of crates.
- TranZit - Located on the second floor of the barn in Farm.
- Die Rise - Randomly spawns in one of the four elevator shafts in the building with the power switch. It trades these positions between games with Juggernog, Mule Kick and the Pack-a-Punch Machine.
- Mob of the Dead - In the Citadel Tunnels, near the door that leads up to the Warden's Office area.
- Buried - In the room next the entrance to the mansion, near the teddy bear location.
- Origins - Not physically present in the map. Can only be obtained through the Der Wunderfizz machine and the Rituals of the Ancients.
- Shadows of Evil - Randomly switches places with Speed Cola and Juggernog randomly through the districts. A yellow bottle marks its location.
- The Giant - Spawned randomly at any of the Perk-a-Cola machine locations, aside from the hidden machine.
- Der Eisendrache - Located to the right of the castle entrance, right under the bridge looking out.
- Zetsubou No Shima - Randomizes locations with Speed Cola and Stamin-Up.
- Gorod Krovi - In the first room of the Tank Factory, near its entrance.
- Revelations - To the Origins Side of the map by the power generator to the right of the mystery box location.
- Nacht der Untoten (remastered version) - Can only be obtained from the Der Wunderfizz machine or the Perkaholic or On the House GobbleGum.
- Verrückt (remastered version) - Right next to the MP40 purchase on the German side. Can also be obtained from the Der Wunderfizz machine or the Perkaholic or On the House GobbleGum.
- Shi No Numa (remastered version) - Will spawn randomly in one of the four huts. Can also be obtained from the Der Wunderfizz machine or the Perkaholic or On the House GobbleGum.
- Kino der Toten (remastered version) - In the southern part of the alleyway next to a barrier. Can also be obtained from the Der Wunderfizz machine or the Perkaholic or On the House GobbleGum.
- Ascension (remastered version) - Can only be obtained from the Random Perk Bottle, Der Wunderfizz machine or the Perkaholic or On the House GobbleGum.
- Shangri-La (remastered version) - Will spawn randomly in the mines (changes spawn with Deadshot Daiquiri, Widow's Wine, and Stamin-Up). Can also be obtained from the Perkaholic or On the House GobbleGum.
- Moon (remastered version) - Located on the first floor of the laboratories. Can also be obtained from the Perkaholic or On the House GobbleGum.
- Origins - Not physically present in the map. Can only be obtained through the Der Wunderfizz machine, the Perkaholic or On the House GobbleGum, and the Rituals of the Ancients.
The Double Tap machine is large, with a yellow and orange paint job, with some of the paint having come off. On the front of the machine there is a large bottle cap with the Double Tap icon on it. On this cap is a bloody handprint. Beside it at the top is a quote that says "Ice cold" and under that is a price that says "10¢". The middle of the machine has a ribbed metal design with a blood splatter on it along with the machine's coin slot and dispenser. Under that is a quote that says "Double Tap".
Double Tap II/2.0
The Double Tap II/2.0 machine is slightly thinner, the icon on the bottle cap is replaced with the Double Tap II icon, the bloody handprint is missing, the ribbed metal design is smaller, the "Double Tap" quote is replaced with "Double Tap II" and the II are made from bullets (in Black Ops II), and the paint job is newer.
- According to Tank Dempsey, Double Tap Root Beer is "chewy".
- In Der Riese, Edward Richtofen does not like the Double Tap Root Beer's jingle. However, while waiting for the Pack-a-Punch Machine, he hums the Double Tap Root Beer jingle.
- Richtofen's hate for the jingle is also mentioned by him when obtaining Double Tap Root Beer in The Giant.
- In the French version of the game, it is named Double Tap Lemonade. In the Italian version, it is named "non-alcoholic Double Tap beer".
- The beer bottles in Die Rise look almost like the Double Tap Root Beer bottles, except they are blue.
- At the end of the Double Tap jingle, one can hear someone (possibly the singer) laughing quietly.
- A cut model for Double Tap Root Beer for the map Shi No Numa can be found in the game files.
- In Origins, one can acquire Double Tap II for free by spending 30000 points in a match and acquiring it from the Rituals of the Ancients box. It can be drank regardless of how many perks the player already has.
- Double Tap Root Beer, along with Juggernog, Quick Revive, Speed Cola, Stamin-Up, and Mule Kick, has had its icon that appears in the HUD slightly altered between the release of Die Rise and Mob of the Dead for Call of Duty: Black Ops II. The background appears more red now, identical to the Vulture Aid background.
- In Shadows of Evil, the bottle displayed on the box beside the gate leading to the districts is different from the Juggernog and Speed Cola bottles, as instead of showing the icon, it just says "Double Tap".
- During the second half of the original jingle, one hear someone repetitivly saying Double Tap.
- The backing track used for the Double Tap Root Beer jingle comes from a stock track entitled "Slapstick Dick".