And for a short moment I thought I might have done something to offend him, but the man politely explained his reasoning for refusing the gesture — disease.
Keith Nelson founded St Martin's Organic Coffee House in St Martin's Street in 1979 and prides himself of being the proprietor of one of the cleanest venues in the city.
Care and cleanliness saw the popular coffee house awarded a five star hygiene rating in 2021, as in previous years, as well as giving customers confidence that it is a safe place to come into.
I spoke to Keith two years after we first met to find out how he turned out to be so right.
"There are all sorts of infections you can get from just shaking hands," he told, "and it's not just colds and flu."
Keith said he had not shaken hands with anyone in 'probably a few years' adding: "I've never been happy doing it. It seems strange that people want to do that. It's just an old custom.
"Why should you shake hands with somebody and take that risk? We used to have a lot of salesmen coming in and they would come up to the counter and they would put their arm over the top of the counter.
"When I would say 'we don't do that', they would look surprised. You don't know whether they have washed their hands. There's probably nothing wrong with shaking hands if you are dousing your hands in alcohol afterwards.
"I can't remember the last time I had a cold or flu or anything like that."
St Martin's also insists on customers wearing 'proper masks' to help stop infections.
"Not very many, but some people just come in with a glass facemask and I think they think a glass one is okay because hospital staff wear them, but they all wear a paper mask underneath — or some people will just wear a scarf."
The shop has been cashless since before the pandemic to the cash carrying a range of germs.
In the early stages of the pandemic the coffee house made the controversial switch to putting tea in mugs rather than teacups.
"First of all I thought as a coffee shop we need to minimise everything. We decided not to have cups, jugs and tea strainers. For one it creates an awful lot of clutter and weight for customers to take."
Another reason, Keith said, is that it minimised the surface area for bacteria.
Not only does the coffee house make sure it's safe from infections, but boasting a full menu of organic food shows that Keith and his team consider every aspect of public health when provide their service.