Started a batch of Cooper's Nut Brown Ale yesterday. During the sanitizing I
broke my only hydrometer and was unable to measure OG.
I used 2lb of Muntons spraymalt extract. The total volume was 5 gallons
(US.)

What would be a good guestimate of the OG? I will be buying two replacement
hydrometers (1 spare) to measure the FG.

John