BIAB - Dunk Sparging (sort-of) question

[ArnoldTheBat]

Hi,

I've done a few BIAB batches and I think I've probably misinterpreted what dunk sparging means, what I've been doing is:

- Full volume single temperature mash. 90 mins
- Raise temperature to mash out and hold there.
- Lift grain bag out of the boiler, let it drain a bit, dunk it back in the wort, lift again, let it drain a bit, dunk it, etc. After a while of that lift out the bag for the last time and squeeze.

Sort of like making a cup of tea when you don't have enough time.

However I think this was based on my misunderstanding of what a dunk sparge is (this actually seems to be dunking the bag in fresh water, heated to mash temp, which makes a lot more sense!).

I'm getting 75-80% efficiency with my above method, and it's super simple, so I'm not too fussed about adding complexity if the only benefit is efficiency.

Guess my question is: Is there anything wrong with the above process (oxidation from dunking repeatedly into the hot mash)? Should I even bother doing the dunking thing?

Thanks!

 

[wilserbrewer]

Nothing wrong with what your doing, but dunking back in the same wort is sort of just like stirring the mash, and stirring is easier.

Sparging is typically done with fresh water rather than wort.

 

[Rdom]

75-80% efficiency is pretty darn good! Like wilserbrewer said, you can accomplish the same thing by stirring. Probably no need to sparge at all given your numbers.

 

[ArcLight]

>>- Full volume single temperature mash. 90 mins

Unless you are mashing very low, like 145F, I don't think 90 minutes is accomplishing much. The key to high BIAB efficiency is a tight crush. You might not even need 60 minutes.

- Raise temperature to mash out and hold there.

Probably not needed. I never mash out. I don't think this will have a meaningful impact on your extraction rate. The water is no where near saturated and can hold the sugar.


- Lift grain bag out of the boiler, let it drain a bit, dunk it back in the wort, lift again, let it drain a bit, dunk it, etc. After a while of that lift out the bag for the last time and squeeze.

I mash with around 5 gallons, lift, drain, SCOOB (Squeeze the Crap Out Of the Bag)
then set it in a pot with 3 gallons of fresh water for 5 minutes, so its submerged. Mix it in, and stir it around every minute or two. Then raise the bag, drain, SCOOB, and pour into the main mash.


>>I'm getting 75-80% efficiency with my above method, and it's super simple, so I'm not too fussed about adding complexity if the only benefit is efficiency.


75-80% is excellent and I wouldn't add any more complexity. I'd simplify it by not mashing out (i.e. raising the temperature) and I'd shorten the mash to 60 minutes.
Just make sure you have a tight crush.

>>Guess my question is: Is there anything wrong with the above process (oxidation from dunking repeatedly into the hot mash)? Should I even bother doing the dunking thing?

No Oxidation risk from this.

 

[ArnoldTheBat]

That sounds great (always like to simplify), thanks very much for the advice.

 

[RM-MN]

>>- Full volume single temperature mash. 90 mins

Unless you are mashing very low, like 145F, I don't think 90 minutes is accomplishing much. The key to high BIAB efficiency is a tight crush. You might not even need 60 minutes.

- Raise temperature to mash out and hold there.

Probably not needed. I never mash out. I don't think this will have a meaningful impact on your extraction rate. The water is no where near saturated and can hold the sugar.


- Lift grain bag out of the boiler, let it drain a bit, dunk it back in the wort, lift again, let it drain a bit, dunk it, etc. After a while of that lift out the bag for the last time and squeeze.

I mash with around 5 gallons, lift, drain, SCOOB (Squeeze the Crap Out Of the Bag)
then set it in a pot with 3 gallons of fresh water for 5 minutes, so its submerged. Mix it in, and stir it around every minute or two. Then raise the bag, drain, SCOOB, and pour into the main mash.


>>I'm getting 75-80% efficiency with my above method, and it's super simple, so I'm not too fussed about adding complexity if the only benefit is efficiency.


75-80% is excellent and I wouldn't add any more complexity. I'd simplify it by not mashing out (i.e. raising the temperature) and I'd shorten the mash to 60 minutes.
Just make sure you have a tight crush.

>>Guess my question is: Is there anything wrong with the above process (oxidation from dunking repeatedly into the hot mash)? Should I even bother doing the dunking thing?

No Oxidation risk from this.

If your grain is crushed very tight, 60 minutes is excessive. I've been getting really good efficiency (80%+) with a 30 minute mash and I've begun experimenting with a 10 minute mash. So far the 10 minute mash has given me about the same efficiency as the 30 or 60 were giving me.

Mash out is important for fly sparging where you will keep the grains at mash temperature for an extra hour or more as you sparge. Mash out will stop conversion before the sparging starts. For batch sparging or BIAB, it serves no real purpose except to make the sugars a little more soluble. The difference in solubility between 155 and 170 is pretty small.

 

[ArcLight]

>>Mash out is important for fly sparging where you will keep the grains

This is a BIAB topic so obviously has nothing to do with fly sparging.
Mashout with BIAB hasn't made much/any difference when I've done it while BIAB.

Furthermore, I don't even dunk sparge at 150, I dunk sparge with room temperature water. The sugar content is low enough that it's nowhere near saturation.

As for less than 60 minute mash, that can work. You also need time for gelatinization so I wouldn't tray and save 20 minutes. It's not like you have to stand there for the extra time. Just come back a little later.
And you will get a little more conversion during those extra 20 minutes if your mash temperature is at 150 compared to 156. The extra mash time
will also makes for a more fermentatble wort.

 

[bford]

Quick question... I do 2 gallon batches BIAB.... I start with just over three gallons of water.. I've just been lifting and squeezing, no extra sparging...

If I wanted to try a dunk sparge... should I do the mash with two gallons and then save one gallon for the dunk?

Thanks peeps!

 

[PRE66_6TART]

Quick question... I do 2 gallon batches BIAB.... I start with just over three gallons of water.. I've just been lifting and squeezing, no extra sparging...



If I wanted to try a dunk sparge... should I do the mash with two gallons and then save one gallon for the dunk?



Thanks peeps!

Yeah, that should be fine. You can split the water up any way you'd like, really. I usually go about half and half, but I'm limited by the size of my mashing vessel. More water in the mash probably helps in couple ways, like making it easier to stir, and holding the mash temperature better.

A couple things to keep in mind. Since the grain is already saturated it will displace a lot of water in the dunk sparge, so make sure your dunk sparge vessel is big enough that it won't overflow. I've made that mistake before. Also the more water you have in the mash, the higher the ph will be, so you can use your water volumes as a way to get the ph you want.

 

[bford]

Thanks! I'm going to try it next time.


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