Wine must be the only everyday product that has such a cavernous gulf between the knowledge of those who sell it and most of those who drink it.

Mainstream wine consumers have minimal wine knowledge and little, if any, desire to know more. What they want is cheap, branded, fruity and unthreatening, and they find exactly that in the supermarkets.

Most wine retailers, on the other hand, are engaged enthusiasts who love wine and love learning about it.

Very often that creates incompatibility between the merchant and the majority of their potential customers, because it’s easy to forget how bewildering and pretentious wine appears to the huge numbers of casual drinkers in the UK.

Because most of them are largely indifferent to wine, we should be realistic about that when talking to them, showing enthusiasm without being preachy. There’s a brilliant, high-profile example of how to do exactly that on primetime television right now. Joe Wadsack does a great job of delivering an easygoing but infectious message about wine for the BBC’s Food & Drink programme.

Meanwhile, everyone who comes into your off-licence to buy wine might be someone who wants to know more. Most won’t be, of course, so the trick is figuring out which are which, and handling each accordingly.

Asking simple questions is the best way to gauge how receptive people are. That might sound obvious – which is precisely why it’s something easily forgotten. “Can I help at all?” is the classic first step. If they say yes, ask follow-up questions, but keep them unthreatening: don’t ask for favourite regions or varieties, for instance, because casual drinkers can quickly become uneasy or embarrassed by having to state any sort of knowledge.

Instead, ask more innocuous questions such as “what wine do you usually drink?” or “do you prefer crisp or soft whites?” Keep the questions going – ask whether they will be drinking it with food, what their top price is, whether they’ve tried particular grapes – and tailor your response to a level they’re comfortable with.

The more they answer, the more relaxed they become, and as the dialogue develops, so does their engagement.

Another fundamental but easily overlooked point is to give people what they actually want. Ensure you really understand and cater for their preferences. Don’t push your own favourites if they aren’t compatible, and never, ever try to sell anything just because you’re trying to get rid of it.

For those who don’t want help, try pointing out something before you leave them to browse, to pique their curiosity. Or make a friendly comment about whatever they bring to the counter – “I drank that with roast beef – it was brilliant,” or “great choice – have you tried this before?”.

It’s all about allowing everyone to get greater understanding of wine – and with it, greater enjoyment. Retailers are often the first point of contact between casual drinkers and the wider world of wine. It’s up to us to encourage those who want to know without alienating those who don’t.