Neil Perry calls it "the best bread in Australia" with a "big depth of flavour, beautiful chew and incredible crust". He loves Melbourne's Baker Bleu sourdough so much he's brought it to Sydney, firing up the oven on the joint venture in Double Bay on Wednesday, September 21.

This isn't Perry's first brush with Baker Bleu owners Mike and Mia Russell. Mike Russell started out in the pastry section at Rockpool Bar & Grill, upskilling at Bourke Street Bakery and Iggy's Bread before relocating to Melbourne and opening Baker Bleu in 2016. The bread is served in hatted Melbourne restaurants such as Attica and Cumulus Inc.

Perry, who is such an unabashed fan of the bread he used to air-freight it to Sydney, put in a call to Russell that eventually led to the Double Bay launch.

"He rang and asked me how many square metres do you need for a bakery?" Russell recalls. "We left Sydney because we couldn't afford to open here. The idea of being able to do it in Double Bay is incredible."

The site is just around the corner from Perry's Margaret restaurant, facing the park on Guilfoyle Avenue. Russell says they've managed to squeeze everything from a "fermentation facility" to a seven-tonne oven into the space.

"If you're buying bread, we stock anything that goes with it: condiments, cheese and charcuterie," Russell explains. It will open with a limited pastry line-up, before expanding the range by mid-October. There are also longer-term plans to add Roma-style pizza later in the day.

So, what makes Baker Bleu's sourdough so good? Russell is equal parts modest and guarded about the secrets of his loaf. He waxes like a scientist about the long fermentation.

"We've refined the process and the range. We don't compromise, we've reinvested in equipment," Russell says. "It's easy to pump and dump if you want to cut corners and that can happen when you grow, but we've always put the product first."

Open Wed-Sun 7.30am-3pm.

2 Guilfoyle Avenue, Double Bay, bakerbleu.com.au