Glasswasher Descaling Guide for Pubs: How Often and Which Products Work
Limescale is the quiet killer of pub glasswashers. It coats heating elements, blocks spray arms, wrecks door seals and turns a machine that should last a decade into scrap inside three years. At Teal Farm we’re in a moderate-hard water area, and descaling is a non-negotiable part of the weekly routine.
Here’s what actually works.
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How Often Should You Descale?
Water hardness dictates your schedule. Check your local water supplier’s hardness rating — it’s measured in mg/l (ppm) or Clarke degrees.
Soft water (0–100 ppm): Descale monthly. You’re in a forgiving area, but don’t skip it entirely.
Moderate water (100–200 ppm): Every two weeks. This is roughly where Washington NE38 sits. We descale every Sunday during the weekly deep clean.
Hard water (200–300 ppm): Weekly descale is essential. Scale builds faster than most operators expect.
Very hard water (300+ ppm): Twice weekly. If you’re in Kent, Essex or parts of the Midlands, you need a water softener fitted alongside your descaling routine — descaling alone won’t keep up.
If your glasses are coming out with a white film or your wash cycle is taking longer than usual, you’re already behind. Don’t wait for a fault code.
Citric Acid vs Commercial Descaler: Which Wins?
Citric acid is the budget option and it genuinely works for light-to-moderate scale. It’s food-safe, biodegradable and cheap in bulk.
[Citric Acid 1kg Food Grade – Amazon](https://amzn.to/4ukKRuU
Use roughly 100g dissolved in warm water per descale cycle. It’s slower-acting than commercial products but fine for regular maintenance descaling where scale hasn’t been allowed to build up.
Commercial glasswasher descaler is worth the extra cost when you’ve let things slip, when you’re doing a machine onboarding clean, or when you’re operating in very hard water. Products like Chemex or Diversey formulations contain stronger acids (phosphoric or sulphamic) that cut through heavy deposits faster.
[Commercial Glasswasher Descaler – Amazon](https://amzn.to/4ukKRuU
The honest answer: use citric acid weekly for maintenance, and a commercial descaler monthly for a deeper clean if you’re in hard water territory.
Step-by-Step Descaling Process
- End of service. Wait until the machine is cool enough to work with safely.
- Empty and rinse the tank. Remove all glasses. Drain the wash tank completely.
- Remove and clean the filters. Scale lodges in filters and blocks circulation. Rinse them under hot water.
- Mix your descaler. Follow the manufacturer’s dilution rate. For citric acid, 100g per 5 litres of warm water.
- Fill the tank and run a cycle. Let the machine run two to three full cycles with the descaling solution.
- Soak spray arms separately. Remove the upper and lower spray arms and drop them into your descaling solution for 20–30 minutes. Scale in the spray holes kills wash performance fast.
- Rinse thoroughly. Run three full rinse cycles with clean water before returning the machine to service. Descaler residue on glasses is a food safety issue.
- Check door seals. Wipe with a damp cloth and inspect for scale cracking. Replace seals before they fail.
The Drain Pump Rule
Never descale without checking your drain pump afterwards. Descaling loosens scale deposits that then travel through the system — and the drain pump is where they collect. A blocked drain pump will cause the machine to fault or flood. Clear it every time you descale.
One More Thing
Equipment costs are only part of the picture. If your labour percentage is running away from you on wash-up shifts or your VAT position isn’t clear in real time, the glasswasher is the least of your problems.
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