Mash problem?

[Brewed_Force]

I'm still getting to grips with my new boiler (tea urn) and the first two BIAB brews have resulted in lower than expected post boil OG, about 10 points down. I am thinking that this is the result of poor mash efficiency. My temperatures have been good, losing 1 degree after 60 minutes, but I only stirred at the beginning, to eliminate dough balls. Should I have stirred during the mash too ? Would that explain the low OG ?

 

[strange-steve]

It's possible, I'd definitely recommend giving it a couple of stirs mid-mash. How long do you mash for? Do you perform any kind of mash-out or sparge? What BHE are you getting currently?

 

[Rodcx500z]

Do you measure og at mash temp, if so it needs to be 20c this is the temp hydrometers are calibrated

 

[Brewed_Force]

I do a cold water sparge after a 60 minute mash, then squeeze the living daylights out of the bag. The post boil OG was derived via the Brewer's Friend temperature compensation tool.

 

[Davvy]

I do a similar method with a tea urn, and my last 2-3 brews have given 71-74% efficiency.
Is this anywhere near your results ?

Yes I would defiately like to improve , and have on occasion hit around 82% efficiency , but have hit a bit of a brick wall in this quest !
It could be the case that if you milled yourself, or your malt supplier does a "Fine mill" product this may help (???) So, more of the starch would be available for the enzymes to work on producing more sugar at mash. Have not tred it myself, but as I say it is a quest.....

 

[Rodcx500z]

I do a cold water sparge after a 60 minute mash, then squeeze the living daylights out of the bag. The post boil OG was derived via the Brewer's Friend temperature compensation tool.

I always cool my sample to 20c then take a reading if it's to low you can add a bit more fermentables to bring it up or liquoire back to bring it down

 

[Gerryjo]

I always cool my sample to 20c then take a reading if it's to low you can add a bit more fermentables to bring it up or liquoire back to bring it down

Invest in a refractometer with ATC as this gives an accurate reading with only a few drops of wort pre/post mash and boil then use your hydrometer post ferment.