This particular off-flavour was something that I have encountered before over the years, a rather sickly, cloying, sour-cream note. Asking the question on Twitter, several people suggested it might be butyric acid, which according to various descriptions on the Internet certainly fits the bill. It is described on this website as “Rancidity, Baby vomit, cheesy, putrid, spoiled milk or butter”.
I’ve never worked in a professional capacity in the licensed trade, and I’ve never had any formal training in beer tasting. But I’ve drunk enough beer to know that sometimes it just doesn’t taste right, often for reasons that it’s hard to put your finger on. The site I linked to lists eighteen different recognised off-flavours in beer, some of which I recognise, although others don’t really ring a bell. I’ve also often encountered beers with a distinct woody note, but not served from wooden casks, which doesn’t exactly match up with any of those listed.
If you’re familiar with a beer, it’s not too difficult to tell whether or not it tastes right. Bit in these days of ever-changing guest beers, many of which you will only try once, and of unprecedented experimentation with different flavours, it can be extremely difficult to tell whether or not a beer is actually meant to taste as it does. Added to this, it’s not unknown for brewers to turn a defect into a feature in one-off beers, such as the perhaps apocryphal case of the batch that was badly affected by the common fault known as diacetyl, which results in a pronounced caramel note, but ended up being badged as “Butterscotch Porter”. It’s also the case that, in small doses, some of the off-flavours, such as phenol, can be regarded as desirable characteristics.
From time to time I’ve had pints that to my taste are distinctly off, but others found no problem with. They might have just been being ignorant or perverse, but equally it’s possible that they just didn’t notice, as people’s susceptibility to different off-flavours varies widely. In the summer of 1984, when I was living in that part of the world, Gales Brewery in Hampshire experienced a yeast infection, which to me gave their beer a very distinct and unpleasant taint. But some people couldn’t detect it at all. After about three months, it faded away, but some might argue that their beer was never the same again. There’s a well-known off-flavour in cider known as “mouse”, which actually does impart an oddly furry texture to the drink. But, again, some people can detect it and others simply can’t.
People’s aversion to different off-flavours also varies. I’m not too bothered about diacetyl in small doses, but others really can’t abide it. And, in the discussion about butyric acid, one person said that a hint of “baby sick” was one of his least disliked off-notes, whereas I find it foul in any degree.
The burgeoning range of flavours and styles, and the sheer number of brewers, means that off-flavours in beer are something that isn’t going to go away. It’s not reasonable to expect the general drinking public to be constantly on their guard to spot them, so brewers and retailers need to take ownership of the issue, be alert to it, and not just breezily dismiss it as all part of the rich tapestry of life. And maybe there is an opportunity to do more to educate interested lay drinkers in being able to identify the various taints.