Britons Hunter (pictured right) and Purchase were leading for much of the final at Eton Dorney, only to be pipped at the last by Danish duo Mads Rasmussen and Rasmus Quist.
"I felt a bit dejected and deflated at the end," Hunter told Eurosport. "We led for so long and to have it snatched away in the dying moments was heartbreaking.
"It was the ultimate for me to win on home water. It's what I dreamt of. To not do that was hard.
"In the final we did our best race - there was nothing we could have done better. The Danes were something else.
"They haven't won anything really since the World Championship in 2007 but they did it when it mattered - they were worthy winners.
"We tried everything to keep ahead, but they pulled it out of the bag. Hats off to them.
"I was made to eat my words before the Olympics - I said then that there was no way any boat would come through a British crew if it was leading in the closing stages.
"[Zac and I] looked one another in the eye afterwards and knew we had given everything."
However Hunter's spirits have been picked up by the messages of congratulation he and Purchase have received.
"The British public have been phenomenal. They have treated us like heroes," he said. "I wish I could thank everyone personally for their kind words. It has helped me take pride in what we have achieved.
"On the Tube (London Underground) yesterday people were staring at me and someone asked 'Are you Mark Hunter?'. When I said 'yes' and showed them the medal, the whole carriage wanted to have their picture taken with me.
"Olympic fever is having a massive impact on everyone."
Should Hunter compete in the next Olympics in Rio in 2016, he will be 38 years of age.
He is unsure of what the future holds - but has high hopes that Purchase, eight years his junior, will appear at two more editions of the Games.
"I'm going to take a couple of months off to switch off then I will return to the drawing board and see what to do," he revealed.
"I'm struggling to think about what I'm going to do next week, never mind whether I'll be in Rio in 2016. I just want to spend time with friends and family for the moment.
"Zac is a massive talent. He is a lot younger than me and he has another two Games in him possibly.
"What he achieves is down to how he deals with what happened [at Eton Dorney]; how he adjusts."
Mark Hunter is part of the BMW London 2012 Performance Team. BMW is the Official Automotive Partner of London 2012, for more information visit london2012.bmw.co.uk or visit the BMW Group Pavilion at the Olympic Park #bmwpavilion