Mashing efficiency/OG higher than expected

[DiBosco]

Folks,

My latest brew used 3kg of Maris Otter and 300g of crystal malt, with 120g in total of hops. After boiling, I ended up with 21 or so litres of beer that is currently fermenting.

When I've used similar quantities I've ended up with an OG (after boil) that gave me an ABV of about 3.8%. This time, I've ended up, somehow with an OG of 1048, which should give me an ABV of more like 4.8%!

Is it possible that my mashing efficiency has shot up to better than 90%? I don't think I've done it differently to last time and 75% seems to be what most people manage and, I think, I did in my previous brews.

Has anyone else experienced huge variations in OG with identical amounts of grain? Anyone got any ideas what might have changed this time? I am farily sure I didn't measure the OG incorrectly!

Thanks!

 

[Slid]

Does your hydrometer that gave you 1048 still show 1000 for water at 20C?

Could be a calibration issue, as I would query the efficiency at > 90%

 

[simon12]

I once got 120% efficiency due to the Wilko hydrometers not being dish washer safe or something else through it off.

 

[clibit]

I think it's unlikely you efficiency has suddenly rocketed to 90+%. It's more likely a weight of gravity measurement was wrong.

 

[DiBosco]

I'll check the hydrometer later in water. I am sure it wasn't an incorrect reading, someone else checked it as well!

I'm wondering whether it could be some non-fermentables that are in the liquid. after mashing there was a LOT of grain coming out of the mash tun and I had to do a lot of recycling of the wort.