You should never leave a garnish in your drink if you want the flavor to be consistent.
Harrison is quick to clarify that this is just his personal preference, but he always takes the garnish straight out of his drink when it arrives.
"When a garnish is in a drink, it impacts the drink, and it impacts it for a long time," Harrison explained.
This means as you drink more and more of your beverage, the impact of the garnish is heightened on what's left — the flavour of your drink is constantly changing.
If you take the garnish out straight away, the drink's flavor profile will stay the same as when it arrived on your table.
Likewise in a Martini, Harrison explained, the three basic ways to serve it are with a twist, an olive, or an onion. But not all lemons, olives or onions are built the same. Each variety used by each bar differs and changes the profile of the drink.
"For me, if I want the perfect drink, it's just easier to take it out," Harrison said.
Be specific with the gin you order — and always choose your tonic.
Despite our better judgment, most of us will likely walk into a bar and ask for a vague "gin and tonic." Or worse, you order your favorite premium gin because you know you like it, and then the bartender fills the rest of your glass with a low-quality tonic water from a gun.
"It's a bit like walking into a restaurant and going, 'I'll have some food, please,'" Harrison said.
"If you don't ask for something that you like, you leave it in the bartender's remit to give you a drink.
"You might personally not like the gin or the tonic that they've given you. So you are going to get a drink that becomes something you sit there with and go 'eurgh,' but you've just given the person some money, you're going to consume it."
Instead of just asking for a G+T, it pays to be specific Harrison said. Ask for a gin that you like, and the tonic that you like to pair it with.
"If you're going to give somebody some money, then you should demand what you want to have as a drink," he said.
"A little bit of knowledge can actually make your consumption experience a million times better."