September 27, 2021

Myth buster: Do bubbles on the glass mean it’s clean


In this month’s myth-buster we tackle the mistaken idea that bubbles clinging to the inside of a glass mean it’s clean.

Mention ‘bubbles’ or ‘bubbly’ in a food and drink context and it likely conjures up images of champagne. Celebrations, popping corks, fizz flowing and guests with bubbly personalities who are the life and soul of the party. At the risk of bursting that bubble, the truth is that bubbles are not always a good thing – and when it comes to glassware they can actually be a warning sign that all is not well.

We know what you’re thinking. No one wants flat beer! This of course is true, bubbles of carbon dioxide are a must even in cask ale where they occur naturally and lend a more gentle effervescence than you find in lager or other keg beers. But bubbles need to be in the right place. That’s why some brewers insist their beer is served in special, ‘nucleated’ glasses. These have tiny etchings, usually inside the base of the glass, to encourage the release of bubbles at a steady rate. This can make head, flavour and aroma last longer so the beer tastes better right up until it’s finished.

These good bubbles will be on the move, rising upwards, inside the glass of beer. But if you spot bubbles that seem to have lost the party spirit – clinging to the side like the wallflower at a dance or the party guest who stays in the kitchen all night – you’re looking at beer that’s been poured into a dirty glass.

When bubbles go bad

The location of the bubbles makes the difference. The reason they stick to the glass in a cluster is because they’ve been trapped by oily residue or other dirty nasties that haven’t been properly washed off. First and foremost, no one wants to drink from a dirty glass, but the sort of residues these bubbles indicate are also just the kind of thing that can make beer go flat and cause the head to collapse.

It could be hop oils from beer, grease or fat, or even leftover soap that’s grabbed those bubbles. But whatever it is, it shouldn’t be there – so if you spot clusters of bubbles on the side of one glass, it’s worth treating it as a prompt to check all your glasses. Some might say, it’s just one glass, swap it for another and move on. But flat beer can cost you money, not just in returned pints but in lost custom from drinkers who don’t voice complaints but vote with their feet instead.

Some say that a type of product called ‘renovator’ is the answer to your prayers. These are designed for regular use to combat a build up of oily residues and restore glass to its original condition. But with the right detergent, used properly, it’s possible to avoid both the need for renovators or problems with dirty glassware. Our Avani CLARITY is one such detergent. It’s concentrated and low foaming and its balanced formulation is designed to be strong enough to prevent protein build-up on the surface of glassware. Find out more about Avani CLARITY glassware cleaner, and don’t forget the rinse aid.

Best practice for washing beer glasses

● Wash beer glasses separately from crockery, including mugs and cups, to avoid fatty residues spreading to glassware.

● Remove any lipstick from glasses before they go into the glasswasher.

● Keep your glasswasher scrupulously clean. Be aware of whether local water is soft, or hard enough to need products to tackle limescale.

● Leave your glasswasher open, to air it, when the bar is closed.

● Don’t dry glasses with a cloth. This can leave germs or fibres behind in the glass.

● Use our latticed black shelf tiles or white glass storage mats to allow glassware to air dry. It’s important that air is allowed to circulate around upturned glasses, to prevent unwanted condensation and smells, and to keep the rim perfectly clean for the next drinker.

Knowing what clean looks like

Once upon a time we had to rely on the far-from-accurate ‘water break test’ to evaluate glassware hygiene. (Water supposedly sheets down the inside of a clean glass instead of running in streaks or spots.) But now there is SMART GEL. This reacts with organic residues on the glass surface to give a fast and accurate colour reading, so you can pinpoint hygiene problems at the point of dispense.

As long as you stay on top of glassware hygiene, all your bubbles should be the partying kind – but don’t be afraid to take action if bubbles go bad.

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