Dunk Sparge and/or Mash Out

[BinghamtonEd]

So I am looking to brew a batch that will push the limits of my setup, to the point where I'm going to dunk sparge the bag in my fermentation bucket and then use that to top off the kettle.

My question is this :
After mashing for 60 min at 152, should I move to a 10-minute mash out at 170, or should I skip the mash-out and just dunk that bag in the bucket and combine the two?

For reference, the grain bill is 13.5lbs, and the mash thickness will be 1.5qt/lb. Assuming I lose .1g/lb overall to absorption (with squeezing the bag), this would leave me with about 3.7. I plan to have 2g of 170-degree water waiting in the bucket for the dunk sparge, to get me a pre-boil volume of around 6.7 (probably slightly less). My only concern with not doing a mash-out first is that placing the grain in the 170-degree water in the bucket will cause the temps to drop below 170.

I am leaning towards a mash-out, followed by the dunk sparge and squeezing.

 

[Rockn_M]

What I do and it has worked so far is after the 60 min mash I increase the temp to 170 for 10 min. After the ten min is up I remove the grain bag and let it drain for a while. Once it has stopped dripping I move the grain bag to another bucket that I can squeeze as much liquid out as possible. If you’re doing this bare handed, you'll want to wear gloves. Anything I get from the squeeze I dump back into my wort and continue with hops schedule.

 

[BinghamtonEd]

That's what I'm leaning towards, but adding a dunk sparge on the end, not just squeezing, to get to my volume. Even if, theoretically, I were to get 0% grain absorption by squeezing all the water out, I would still be short of my pre-boil volume.

 

[Rockn_M]

That's what I'm leaning towards, but adding a dunk sparge on the end, not just squeezing, to get to my volume. Even if, theoretically, I were to get 0% grain absorption by squeezing all the water out, I would still be short of my pre-boil volume.

If my target wort size is 5 gallons I usually will start with about 6.5-6.75 gallons of water. After grain absorption and boil off I'll end at the 5 gallon mark. There are numerous BIAB calculators out there that you can use as a reference.

 

[BinghamtonEd]

Maybe I'm not being clear...the issue is not how much I need pre-boil. I know how much I need pre-boil, I know what my boil-off rate is, and can estimate grain absorption and trub losses, and know how to squeeze the grain bag.

The issue is that it is not physically possible to do a full-volume BIAB in my pot, hence the dunk-sparge to get water to top-off to the 6.7ish I need. The question was whether or not a dunk-sparge at 170 with grains from a 152 mash would be a substitution for a normal BIAB mash-out at 170. My gut tells me that it would be safest to just do my mash-out, then dunk.

 

[the_trout]

I do a 170* mash out then sparge. Efficiency usually comes in 75-80. Its a good method. Simple and effective.

 

[1MadScientist]

Maybe I'm not being clear...the issue is not how much I need pre-boil. I know how much I need pre-boil, I know what my boil-off rate is, and can estimate grain absorption and trub losses, and know how to squeeze the grain bag.

The issue is that it is not physically possible to do a full-volume BIAB in my pot, hence the dunk-sparge to get water to top-off to the 6.7ish I need. The question was whether or not a dunk-sparge at 170 with grains from a 152 mash would be a substitution for a normal BIAB mash-out at 170. My gut tells me that it would be safest to just do my mash-out, then dunk.

Make sure your pH is below 6, else you will get tannins.

It's best to squeeze and get what you can and then add top up water to get your volume.

 

[JohnSand]

I made a batch like this yesterday. I did not mash-out, I used a 170 dunk sparge. Mash efficiency was 70%. I also squeezed the bag in a colander after sparging. I also topped off the boil kettle with 1/2 gallon of tapwater.