On this page
- Overview: What CoEA Actually Does
- Key Stats and Acquisition
- Mechanics: Three Gems Into One
- Energy Formula: How Each Ailment Builds Up
- Maximum Energy and Socketed Spell Cast Time
- Recommended Support Gems
- Build Use Cases: Three Trigger Routes
- Common Mistakes: Why It Won't Trigger
- Video Walkthrough and Timestamps
- Frequently Asked Questions
- Changelog
- Sources and Verification
Overview: What CoEA Actually Does
Cast on Elemental Ailment is a Meta trigger gem: you socket a Spell into its Socketed Spell slot, and whenever your attacks or skills pile up enough elemental ailments (Freeze, Shock, Ignite) on enemies, the gem spends accumulated Energy to automatically cast that Spell. It is not a damage skill on its own — it is an engine that turns 'apply ailments' into 'auto-cast a Spell'.
Why can't you find Cast on Freeze anymore? In 0.3.0 GGG merged Cast on Freeze, Cast on Shock and Cast on Ignite into Cast on Elemental Ailment. The old names survive only as search aliases and migration notes; the current canonical page is CoEA. Any guide still telling you to socket a standalone 'Cast on Freeze' is outdated.
Its value is decoupling 'spreading ailments' from 'dealing burst': your main skill keeps applying ailments while CoEA automatically slams a high-damage Spell like Comet, Eye of Winter or Frost Wall at the right moment. The cost is Spirit reservation, a required Socketed Spell, and a trigger cadence that depends heavily on how efficiently you apply ailments.
- Essence: an ailment-accumulation engine that auto-casts a Socketed Spell.
- Origin: merged from Cast on Freeze / Shock / Ignite in 0.3.0; old names retired.
- Energy currency: generated separately by Freeze, Shock and Ignite.
- Key limits: needs a Socketed Spell, costs Spirit, cadence depends on ailment uptime.
- Common traps: Missing Socketed Skill, no Energy gain, single-target boss stalls.
Key Stats and Acquisition
- Category
- Meta / Trigger
- Tagged meta, trigger, persistent. Deals no direct damage; only triggers.
- Spirit reservation
- High (verify on current client)
- Competes with other Persistent Buffs / Heralds for your Spirit budget.
- Acquisition
- Uncut Meta Gem
- Unlocked via an Uncut Meta Gem from campaign or drops; a core late-game engine.
- Socketed Spell
- One Spell required
- An empty slot reports Missing Socketed Skill and the gem does nothing.
- Maximum Energy
- Set by Socketed Spell cast time
- Longer cast time = higher per-step Energy cap; the core gearing trade-off.
- Quality
- Improves Energy gain
- Higher quality usually boosts Energy per ailment, directly raising trigger rate.
Mechanics: Three Gems Into One
Merge logic: the old Cast on Freeze / Shock / Ignite each responded to one ailment. CoEA responds to all three, but each ailment contributes Energy under different rules. You no longer pick a gem based on 'I want to trigger on freeze' vs 'on ignite' — one CoEA eats Energy from all three.
Practical impact: the old 'Cast on Freeze mandatory' conclusion does not transfer directly. Now you care about which ailment your main skill reliably applies, and how fast, plus which ailment is most efficient in the current scenario. In dense maps Freeze triggers fastest; on a single boss where Freeze is hard to sustain, Shock or Ignite may be steadier.
Difference from Elemental Invocation: both touch ailments / elements but are different systems. CoEA is something you equip with a Spell socketed, auto-triggered by ailment accumulation; Elemental Invocation is a separate elemental-charge trigger system. Don't conflate them — pick one as your main trigger engine.
- Old Cast on Freeze / Shock / Ignite merged into CoEA; standalone pages gone.
- One CoEA responds to Freeze, Shock and Ignite simultaneously.
- Each ailment's Energy efficiency differs; choose your main ailment by scenario.
- Elemental Invocation is a different system; don't mix the two up.
Energy Formula: How Each Ailment Builds Up
| Ailment | How it grants Energy | Single-target efficiency | Practical note |
|---|---|---|---|
| Freeze | A lump of Energy when you freeze (or fill freeze buildup) a target | Fastest in dense packs; best for clearing | Stalls on freeze-immune or phase-shifting bosses; needs freeze buildup or chilling ground |
| Shock | Energy on each effective Shock (reaching shock threshold) | Medium; depends on shock threshold and shock magnitude | Stacking shock magnitude amplifies per-shock Energy; good for mid-speed multi-target |
| Ignite | Energy proportional to ignite intensity | Tied to Ignite intensity / Ailment Threshold ratio | High ignite intensity sustains single-target; often paired with Flammability-style scaling |
Maximum Energy and Socketed Spell Cast Time
Energy is not infinite. CoEA has an internal maximum Energy cap, and that cap is set directly by the cast time of the Socketed Spell you slot: longer cast time means more Energy can be stored per step. This is why many builds choose a relatively long-cast-time Spell — it decides 'how heavy a slam can I charge up'.
The cost is cadence: a long-cast-time Spell also triggers less often — high single hit, low frequency. A short-cast-time Spell triggers often but with a lower cap. Mapping usually prefers frequent small slams for faster clears; bossing prefers a fully charged heavy slam.
Triggered Spells still cost Mana: CoEA only 'auto-presses cast' for you; it does not waive the Spell's Mana cost. If your Socketed Spell is expensive, you need a Mana pool, recovery or aura that can sustain continuous auto-casts, or the auto-cast gets interrupted and you bottom out.
- Max Energy cap scales with Socketed Spell cast time; long cast = high cap.
- Long cast: heavy but infrequent; short cast: light but frequent.
- Boss = charged slam, clear = fast slam is the common trade-off.
- Triggered Spell still costs Mana; sustain your blue pool.
Recommended Support Gems
- Boundless Energy
- Core
- Directly raises Energy cap / gain efficiency; one of the most core CoEA supports.
- Nearly every CoEA build runs it — it decides how full and how often you slam.
- Energy Retention
- Core
- Slows Energy decay or improves retention, widening the trigger window.
- Especially valuable in boss stall scenarios.
- Considered Casting
- Core
- Improves trigger stability / effective cast time of the Socketed Spell; common pairing.
- Exact benefit verified on current client.
- Spell Cascade
- Situational
- Adds coverage to the triggered Spell, boosting clear speed.
- Limited value on single-target bosses.
- Magnified Area
- Situational
- Enlarges the triggered Spell's area, pairs with AoE Spells for clearing.
- Little help on a pinned boss.
- Spell Echo
- Optional
- Note: a Triggered Spell is NOT re-triggered by Spell Echo; it only affects the same Spell when you cast it manually.
- A common community mistake is treating Spell Echo as 'makes triggering faster' — it does not speed up triggers.
- Controlled Destruction
- Optional
- Boosts the triggered Spell's direct damage, good for burst-focused Socketed Spells.
- Drops crit; confirm your Spell doesn't rely on crit.
Build Use Cases: Three Trigger Routes
Freeze-clear route: a high-frequency freeze main skill (e.g. Ice Nova / Frost Wall + cold attacks) with CoEA socketing Comet or Eye of Winter. Freeze triggers extremely fast in dense packs — ideal for speed clearing. Risk: freeze-immune or phase-shifting bosses stall.
Shock single-target route: steady Energy from high shock magnitude, good for mid-speed multi-target and some bosses. Requires actively stacking shock magnitude (shock threshold + shock multiplier) or efficiency is mediocre.
Ignite hybrid route: high ignite intensity (often with Flammability-style scaling) sustains single-target bosses that can't be frozen. Cost: ignite builds demand higher Ailment investment and are more single-purpose.
- Freeze-clear: frequent freeze + Comet/Eye of Winter; fastest clear, boss-stall risk.
- Shock ST: steady supply via shock magnitude; mid-speed multi-target friendly.
- Ignite hybrid: high ignite intensity feeds single-target bosses; more specialized.
- Cold Caster / Stormweaver are the most common CoEA carriers today.
Common Mistakes: Why It Won't Trigger
Missing Socketed Skill: you have no Spell in CoEA's slot, or the Spell was removed / lives in another weapon set that isn't active. Direct answer: confirm the Socketed Spell slot holds exactly one valid Spell and the currently active weapon set also carries it.
Energy not rising: your ailment application is too weak, or the ailment type doesn't match. E.g. you rely on Freeze but fight a freeze-immune boss, so Energy naturally stalls. Direct answer: check which ailment your main skill actually applies and whether it triggers reliably on the current target.
Assuming Spirit is enough: enough Spirit is necessary, not sufficient. CoEA also consumes the Socketed Spell's cast resource, Mana, and a correct ailment source. Direct answer: verify Spell slot, Mana sustainability and ailment source together.
Minion ailments don't count: Freeze / Shock / Ignite dealt by minions or other non-self skills usually do not generate Energy for your CoEA. Direct answer: ailments must come from your own skill chain.
Thinking Spell Echo speeds triggers: as noted, a Triggered Spell is not re-triggered by Spell Echo. Direct answer: use Spell Echo on the manually cast same Spell, not to accelerate triggers.
- Issue: Missing Socketed Skill.
- Direct answer: slot must hold one valid Spell active in the current weapon set.
- Issue: Energy stalls / single-target boss drops.
- Direct answer: ailment source mismatches the target (e.g. freeze-immune boss); switch main ailment or route.
- Issue: minion ailments don't count as Energy.
- Direct answer: ailments must come from your own skills.
Video Walkthrough and Timestamps
Chronomancer Firebolt showcase author
CoEA Firebolt system in practice
A Firebolt build dealing both fire and lightning, using Flammability to sustain Ignite and feed CoEA Energy — covering map and boss gameplay.
What to watch for: Watch how the author sustains Energy via Ignite and when they switch to the single-target route.
Open source ↗Frequently Asked Questions
Why can't I find a Cast on Freeze gem?
From 0.3.0 GGG merged Cast on Freeze / Shock / Ignite into Cast on Elemental Ailment.
The old names remain only as search aliases and migration notes; the current page is CoEA.
What decides the Energy cap?
The cast time of the Socketed Spell you slot: longer cast time = higher per-step Energy cap.
Exact numbers verified on the current client skill panel.
Does the triggered Spell still cost Mana?
Yes. CoEA only auto-casts; it does not waive the Spell's Mana cost.
Mana-tight builds need a pool, recovery or aura to sustain continuous auto-casts.
Do minion Freeze / Shock / Ignite count for my Energy?
Usually no. Energy comes from ailments your own skill chain applies.
Ailments from minions or other non-self skills generally do not generate Energy for CoEA.
Changelog
- Initial release: merge background, three-ailment Energy formulas, maximum Energy vs Socketed Spell, common non-trigger causes and community questions.
Sources and Verification
GGG official forum Patch Notes and announcements, used to confirm the 0.3.0 three-gem merge and whether Energy / Socketed Spell rules changed this patch.
PoE2DB and Community Wiki provide gem id, tags, Spirit, Socketed Spell fields and hidden behaviors.
Mobalytics Stormweaver / Ice Nova + CoEA builds and the Chronomancer Firebolt showcase, used to cross-check trigger loops, supports and build differences.
Reddit, official forums and comments surface real issues like Missing Socketed Skill, no Energy gain, minion ailments not counting, and the Spell Echo misconception, reproduced on client and answered directly.
Official GGG forums where GGG staff confirm Cast on Elemental Ailment mechanics and patch changes.
Reddit r/PathOfExile2 discussions and help threads for Cast on Elemental Ailment, useful for version feedback and mainstream builds.
Related content
Information is compiled from public web sources and in-game observations; some visuals are original editorial diagrams. External information and images remain the property of their authors or platforms; contact us for removal requests.