would she be continuing on to Rio?
Almost two years on and Grainger appears no closer to making that decision. While fellow London 2012 medallists Sir Chris Hoy, Rebecca Adlington, Beth Tweddle and Victoria Pendleton have all since brought the curtain down on glittering sporting careers, the Glasgow-born rower seems reluctant to follow suit. For now, Grainger remains in a strange state of limbo: neither competing athlete nor retired.
It has been reported in recent weeks that the 38-year-old has set herself the deadline of August to make the call on whether she will return to the GB Rowing fold and resume training. "Oh, have I?" she deadpans. "I haven't heard that." Grainger breaks into laughter.
As things stand she remains undecided, reeling off a long list of pros and cons. "The positives of continuing are being part of the national team and able to train full-time in an incredibly supportive set-up aiming to be the best in the world. [It's] the opportunity to compete in another Olympic Games," she says. "All of that is why athletes say when you retire you are long-term retired because the amazing experiences you've had of being on podiums, you never get that again. It's gone forever. You don't make that decision lightly.
"Some athletes are absolutely sure on the day of competition, 'I'm going to retire, I will walk away happy and content, I can't wait for a new life'. A lot of athletes aren't so sure. I don't underestimate how hard it's going to be. I've had two years out now. The team have moved on, the world has moved on, I'm not getting younger.
"The Rio Olympics is very seductive but the reality is it's a seven-day-a-week training programme. All the great things I've done in the past two years I would have to say no to again. Part of what I wanted to do was open horizons, try new experiences and all the things you can't do as an athlete. If I go back to it, then I close all those doors again."
But Grainger is aware that the window of opportunity to make her mind up is ever narrowing. "Rowing works on an annual cycle with the world championships always the last event of the year at the end of August/beginning of September," she says. "All the athletes have a two-to- three-week break and then it starts again. I've agreed with the powers that be within rowing that I won't be part of this summer."
But she won't be twiddling her thumbs over the coming weeks, having signed up as a BBC pundit for the Commonwealth Games. While relishing the prospect, Grainger admits it feels "a bit strange being on the other side" having experienced the magic of a home Games in London.
"The biggest thing is probably a bit of jealousy there," she concedes. "They have this incredible event ahead of them and I don't think any of us will really know what it will be like. Before London none of us predicted the scale of interest, success and popularity that took over the country that summer. In a way Glasgow is waiting to blossom into that moment."
While her roving reporting role will see her covering most of the 17 sports at Glasgow 2014, there is one that Grainger admits to having a particular soft spot for. As patron of Netball Scotland she has forged a close bond with the Scottish Thistles team and can't wait to see them in action.
"Scottish netball really has come a long way in a short space of time," she says. "They have a new coach [New Zealander Gail Parata], the attitude is all there and it's become far more professional in the last few years. Expectations have risen, their own as much as anyone else's which is great.
"I think any sport that hasn't had massive international success for a long time can get used to being in that middle phase, so it's nice to see them stepping up and believing they can compete with the best in the world."
Throughout her rowing sabbatical Grainger, a three-time Olympic silver medallist before striking gold two years ago, hasn't been averse to jumping in a boat for fun when the opportunity presents itself. In March, she took part in the annual Head of the River Race, the biggest women's boat event of its kind in the country on the Thames in London.
Grainger desribed it as "300 women's eights storming down the river", and although the race eventually had to be abandoned, it did give her time to catch up with Anna Watkins, her partner in the double sculls at London 2012, along with some rowing greats she had heard of but never met.
"The rest of the crew were all people who have competed internationally for Great Britain and retired over the years," she says. "Some of the girls last rowed in the 1992 Olympics. It was almost like a history of women's rowing all in this one boat. Even people long retired, the mental side doesn't change. We get in the boat and suddenly there's this attitude that it needs to be good, it needs to be fast.
"There was Kate MacKenzie, who I rowed with through the 90s; Elise Laverick, who retired after 2008; Kate Allen, who was an Olympic gold medallist for Australia but now lives here; Rachel Stanhope who was in the 1992 Olympics; Philippa Cross [another 1992 Olympian]; and [Scottish rowing legend] Gillian Lindsay. It was a really classy boat to row in."
In her 2013 autobiography Dreams Do Come True, Grainger quotes tennis legend Billie Jean King as saying: "Pressure is a privilege". The Scot looks thoughtful when asked whether she misses that aspect of competing at the highest level.
"I'm mixed," she says. "There are a lot of retired athletes working for the BBC and some of them say, 'I just don't miss any of that pressure, I'm glad to be able to do things without the stress of trying to be the best anymore', but I think what I really miss from sport is that you have an incredible, obvious purpose and a real goal.
"You have to be the best in every way, not just physically, but mentally, technically and tactically. Even your communication with people, everything tests you and you have to bring your A game in all those different areas. As an athlete, if you enjoy that, you thrive off it. It's a great place to be.
"Then you go into normal life and, in a healthy way, it's not as competitive. There is an element of, 'Oh, really? Am I really challenging myself?'. The last major competition I did was London which was probably the biggest pressure I'll ever feel. It's not comfortable, it's not easy, and like the Commonwealth athletes coming to Glasgow, some of them will be fine with it, but for most people that heart-thumping, sweaty-palmed moment is not something you look forward to."
But it is, she insists, very much a privilege to experience that nerve-jangling sensation. "You put on your nation's kit and go out in front of crowds who have paid money to see you compete - what an honour that is," she says. "As an athlete you do miss those moments because it's pretty special."
o Katherine Grainger is a reporter for the BBC's coverage of the 2014 Commonwealth Games in Glasgow live across the BBC on TV, radio, online and mobile from July 23