2 mashes, different temps into one kettle - will it work out OK

[ShonkytonkBrewer]

So a while ago my son and his mate brought a 3v rig off AHB. They finally got around to brewing this weekend with me as the "tutor/guru" to teach them how to use it all.

A few hiccups - but I think we made beer. How it turns out I'm not sure, but it will be beer.

First problem - I really should have checked the size of the mash tun before we decided to do a double batch.

12kg of grain filled it to the brim with no room for water.

So we split the grain into two batches to mash - with for both to end up in the kettle at then end.

Second problem - I should shold pay more attention to strike temp. Using Brewmate it said strike temp should be 75 for a mash temp of 66.

I think the strike water was too hot because it ended up with a mash temp of 70.

Don't ask me why I didn't think to just add some cold water to bring the temp down - but I didn't even think of that until the brew day was well and truly over.

So we mashed for 60mins at 70, batch sparged into the kettle.

Then mashed the second batch of grain.

My logic at the time was if the first half was mashed too high its creating more unfermentables - therefore a sweeter beer I needed to mash the second one lower to make it a bit drier. Not sure if my logic will work but I figured 20 litres of sweet wort mixed with 20 of dry wort might just end up balanced.

So to cut a long story short...

If I mashed 20litres at 70 and mixed it in the kettle with 20litres mashed at 60 - whats the end result likely to be?

 

[ShonkytonkBrewer]

Is there some formula to use to calculate what the end result will be?


I'm assuming it isn't as simple as thinking that 20l mashed at 70 combined with 20l mashed at 60 will give me the equivalent of 40l mashed at 65


Or is it?

 

[Redreuben]

I don’t have a good feeling about this but let’s wait for the results eh ?
Should be an interesting experiment even if it tells us what not to do or what doesn’t work