Why Vinegar Works in a Dishwasher, and Why the Jar Matters
It’s one of those cleaning tips that shows up everywhere once you start looking. Vinegar in a jar. Upright. Top rack. Empty cycle. I’d seen it recommended on blogs, in comment sections, and all over Reddit. I tried it without thinking much about the mechanics, assuming it worked the way most “natural cleaning hacks” are said to work.
But after reading through long Reddit threads, appliance manuals, and comments from repair techs, I wanted to understand what was actually happening inside the dishwasher — and why the jar matters at all.
Why Vinegar in a Jar Exists
The biggest misunderstanding is how dishwashers start a cycle.
Most machines drain first, before any real washing begins. Anything poured directly into the bottom is usually flushed out almost immediately.
That’s why vinegar goes in a jar. The container delays when it’s released, letting it mix into the water during the main wash instead of disappearing in the first drain.
It’s not about holding the vinegar, but about timing when it actually enters the wash cycle.
What Actually Happens During the Wash
From appliance techs and experienced users on Reddit, the explanation is consistent.
During the main wash:
- water repeatedly sprays and recirculates
- the container slowly releases diluted vinegar
- the acidic solution gets pumped and sprayed throughout the tub
There’s no “steam cleaning” effect. The vinegar isn’t magically vaporizing. It’s simply being introduced at the right moment, in a lower concentration, and carried by water that keeps moving.
That’s why a jar, cup, or shallow bowl works — and why dumping vinegar directly into the dishwasher often does nothing.
What Vinegar Is Good At — and What It Isn’t
This is where Reddit threads get very honest.
Vinegar is effective for:
- dissolving mineral scale from hard water
- reducing calcium buildup on spray arms and walls
- clearing cloudy residue from glassware
- neutralizing some lingering odors
But it performs poorly against grease. Multiple commenters pointed out the same test: vinegar on a greasy spoon does almost nothing. Its strength is descaling, not degreasing.
That’s also why people with hard water see better results than people dealing with food buildup.
Why Citric Acid Keeps Coming Up
One of the most common themes in Reddit replies is that vinegar works — but citric acid works better.
Reasons people prefer it:
- stronger descaling action
- less aggressive on rubber and plastic
- used in most commercial dishwasher cleaners
Users who switched described clearer interiors, unclogged spray nozzles, and longer-lasting results, often after a single cycle. Many treat it as monthly maintenance rather than a frequent fix.
Vinegar, by comparison, is viewed as a workaround — accessible, but not ideal.
Why Some Plumbers Say Not to Use Vinegar
This is where opinions diverge, but the reasoning is consistent.
Plumbers and appliance techs caution that even diluted vinegar:
- stresses rubber seals over time
- can affect plastic hoses and fittings
- causes slow degradation, not immediate failure
That’s why many recommend dishwasher cleaner tablets instead, combined with regular filter cleaning. Vinegar isn’t seen as catastrophic — just unnecessarily harsh if used often.
Why Some People Never Have Problems
At the same time, plenty of users report years of vinegar use with no issues. That usually comes down to a few factors:
- infrequent use
- correct placement in a container
- hard water conditions
- already-clean filters and spray arms
In those cases, vinegar helps without overstaying its welcome.
So Why the Jar, Really?
After reading through all of it, the answer is simple: the jar isn’t about cleaning power, it’s about keeping the vinegar from being drained too early while controlling dilution and avoiding direct contact with sensitive parts.
Where I Landed
Vinegar in a jar isn’t a myth, but it’s not a maintenance plan either. It helps with mineral buildup, not with a dishwasher that’s overdue for real cleaning, and it doesn’t replace basics like clearing the filter or spray arms.
Most Reddit success stories weren’t really about vinegar. They were about understanding how the machine works and using the right solution for the actual problem. Vinegar just happens to be the one people remember.