18 May 2021

What the ‘Taint’ is that? – Part 2

Part 2:

We’re back with the second instalment of our series on common taints. This time, let’s take a look at a familiar off-flavour, TCP. Wonderful for grazed knees, insect bites and mouth ulcers, but no one wants their beer to taste of it!

No. 2 Dichlorophenol (TCP) “Di-chloro-phenol.”

How to detect it:

TCP literally tastes and smells just like the bottles of liquid antiseptic you’ll remember from childhood. It’s that strong-smelling antiseptic odour and flavour associated with hospitals. (It’s worth noting though, that there are a few speciality beer styles in which a subtly phenolic character is intentional. It’s also positively associated with brettanomyces yeast. However, in general, it’s a taint in lager, pale ale, IPA, bitter etc.)

Drinkers might say:

“It tastes like I’m in the doctor’s surgery.”; “Hospital!” “It reminds me of my Grandad’s (coal tar) soap.”; “It sort of reminds me of marzipan.”

What causes it:

At the root of most TCP taint problems is chlorine. It can come from reactions between chlorine compounds in cleaning chemicals and phenols which are naturally present in beer. Heavy use of chlorine-based chemicals can be another culprit, but as tap water is chlorinated this can be a cause too – especially if combined with non-food grade hoses. Very rarely, it can be a fault with the line itself – but if that’s the case you’ll spot the problem from the first day after installation of new lines.

Solutions:

Make sure you always follow usage instructions for chlorine-based products and ensure your cellar is equipped with food-grade hoses. If only certain products in your range are affected with this taint (particularly darker beers, where subtly phenolic flavours are intentional) then consider using a chlorine-free beer line cleaner like Desana MAX fp as a maintenance cleaner. You may need an AvaniSOS L3 treatment to get rid of the taint.

See too, our post on Trichloroanisole because Dichlorophenol (TCP) is also thought to be a precursor to this.