Memory Jar and the old jar hand

[ErkBek]

If I activate a memory jar and have mana floating at the end of my second main phase, does my mana pool empty before I get my old jar hand back?

Oracle text: T, Sacrifice Memory Jar: Each player removes his or her hand from the game face down and draws seven cards. At end of turn, each player discards his or her hand and returns to his or her hand each card he or she removed from the game this way.

[Anusien]

Mana Burn: When a phase ends, any unused mana remaining in a player's mana pool is lost. The player loses 1 life for each mana lost this way. This is called "mana burn." See rule 300.3.

Phase: Each turn is divided into five phases: beginning, precombat main, combat, postcombat main, and end. See section 3, "Turn Structure."

Your mana pool empties at end of postcombat main phase, and your Jar hand does not come back until End of Turn Phase.