Brewzilla Reiterated Mash

[MrJay83]

Hi,

I'm trying a double IPA this weekend in my brewzilla (35l) and I'm wondering if I'm taking the right approach to my mash water.

My grain bill is 8.2kg for a 25l batch so I was going to split that evenly over the two 1-hour mashes. First mash will have 25l and sparge with approximately 6l to 27l for the second mash. Then sparge with another 6l to get to a preboil volume of 29l. I'm assuming a grain absorption of 1l/kg.

And lastly, will the mash be too thin? I see a lot of conflicting ideas about it online. I've also seen lots of BIAB videos and they mash thinner than this without complaints.

Many thanks in advance.
J

 

[RoomWithABrew]

Worth a look if you've not seen it

 

[MrJay83]

Worth a look if you've not seen it

Seen that but following that method it works out at 14.6l for the first mash and 18.7l for the first sparge. The second sparge would only be something like 4-5l which makes me feel like the DH method lends itself to a smaller batch size. I was thinking my figures evens it out a lot more.

 

[RoomWithABrew]

The trouble is larger grain bills reduce your efficiency as you know. By doing a normal / bigger grain bill in the first mash and then sparging to make up your second mash volume you will get better mash efficiency from the first batch. The second batch is going to be much thinner and feel like a mini mash / batch.

Have a look at this graph ( sadly in gallons ) but it might help you decide on the sweet spot you want.

It's courtesy of @doug293cz on the american forum and his full reply and link to spreadsheet is in this thread.

https://www.homebrewtalk.com/threads/vorlauf-and-biab.682085/#post-8924062
post 17 has this graph in.

 

[MrJay83]

Cheers. That post on HBT was an interesting read as well
Weather permitting I'll be giving it a go this weekend so I'll report back with how I got on.

 

[MrJay83]

Done the brew today (still at the boil) and my approach seems to have worked out apart from the double stuck mash. I would hate to think how it would have turned out without rice hulls (double NEIPA).

 

[WonkyDonkey]

Done the brew today (still at the boil) and my approach seems to have worked out apart from the double stuck mash. I would hate to think how it would have turned out without rice hulls (double NEIPA).

What OG did you come out with in the end?
I've toyed with a reiterated mash in the past, biggest grainbill I've done on my brewzilla is 8kg and got an OG of 1078 with a single mash.

 

[MrJay83]

8kg in the 35lt? In one go! Fair play to you. Just had another look at the trail jar (in clean up mode at the moment) and it's saying 1.064.
How long did you mash for? What style?

 

[WonkyDonkey]

8kg in the 35lt? In one go! Fair play to you. Just had another look at the trail jar (in clean up mode at the moment) and it's saying 1.064.
How long did you mash for? What style?

It was a Double Oat Cream NEIPA in the style of Other Half's Daydream, if you're familiar with the style? There was 30% oats in it but that was mostly Oat Malt with some GNO. When I'm going that high I leave regular oats out as you're just asking for trouble!
As for the mash I did a step mash, 40 minutes at 63c then 30 minutes at 72c. Helps with fermentability but keeps the body.
What was the recipe that you were aiming for?

 

[MrJay83]

Don't have the recipe to hand but it was full of oats. I probably should have tried a step mash but as I was doing two mashes I just didn't have the time.
It was a kit and the instructions were a but sparse. Just waded in but this is how you learn.