Just read in newspaper
https://business.financialpost.com/n...lds-new-method
McDonald’s makes tweaks to the Big Mac, Quarter Pounder in quest for a hotter, juicier product
The new bun recipe includes more moisture, which holds more heat, McDonald’s said in a briefing note on the buns. The top of the bun — the crown — will be reduced in height by three millimetres, “allowing deeper heat penetration.” Meantime, the bottom of the bun — the heel — will be increased by three millimetres, “thereby increasing the heat retention,” the briefing note reads.
didn't know 3mm makes a huge difference.