dunk sparge-amount to reserve

[cervid]

So, I'm planning on trying a dunk sparge on the cali common I'm doing tonight.

Not only for increased efficiency, but also to get my grist to water ration to the level where my mash ph is lower.

My question is, how much water do you guys usually pull off for a dunk sparge?

I have 7.9 gallons treated and ready to go. Mashing in 5 gallons would get me to 5.4ph and obviously leave 2.9 to dunk in and a ratio of 1.82.

Mashing in 3.5 would get me to 5.3 ph, with a ratio of 1.27, but I think that is too thick for BIAB..

What are your experiences? I'm inclined to mash in 5 gallons and dunk in the 2.9 for my first go at this method. Do you really notice a huge difference between dunk sparge and slowly pouring the reserved 'sparge' water over the grain bag as it hovers over the pot?

 

[wilserbrewer]

Fwiw, I prefer a pour over sparge for ease of process. Did the dunk sparge a couple times and found it not worth the effort.

Sorry, can't comment on efficiency differences between the two, but I'm also curious.

For me, grain is relatively cheap. Complicating the process for less than a dollar seems counterproductive.

If I feel like batch sparging, I'll use my cooler MT.

 

[PRE66_6TART]

I mash in a 5 gallon pot, so I put my grain in and add water until it's up to the brim, then whatever's left stays in my boil kettle for the dunk sparge. Usually works out to roughly 4 gallons in the mash, and 4 in the sparge. I like to keep my mash pot full to help maintain the temperature.

Doing it this way leaves me with a pretty low water to grain ratio, more like what traditional AG brewers use, but it doesn't matter since I sparge anyway. I think the high water/grain ratio is more crucial to no sparge BIAB brewing, because it makes up for lack of sparging. I always thought of it as the more water in the mash, the more diluted the sugar water is, and therefore less stays behind in the bag. With a thicker mash more sugar is going to be left in the bag initially, but you get it out with the dunk sparge.

 

[cervid]

I mash in a 5 gallon pot, so I put my grain in and add water until it's up to the brim, then whatever's left stays in my boil kettle for the dunk sparge. Usually works out to roughly 4 gallons in the mash, and 4 in the sparge. I like to keep my mash pot full to help maintain the temperature.

Doing it this way leaves me with a pretty low water to grain ratio, more like what traditional AG brewers use, but it doesn't matter since I sparge anyway. I think the high water/grain ratio is more crucial to no sparge BIAB brewing, because it makes up for lack of sparging. I always thought of it as the more water in the mash, the more diluted the sugar water is, and therefore less stays behind in the bag. With a thicker mash more sugar is going to be left in the bag initially, but you get it out with the dunk sparge.

I think it does matter though. Having a really thin mash will raise the ph of the main mash, potentially extracting tannins.

For my first batch, I had 5 gallons in the boil kettle and reserved 3 gallons in a canning pot to dunk in. I do it on a stove top, so pouring over seemed to be a pita for me.

It worked well, my pre boil gravity was 2 points under Beersmith, but my OG was on. I boiled off more than I calculated in beersmith and I was a gallon short. So, I look forward to this next batch as all my numbers should be on.

I think I need to dunk sparge a little longer next time. I just used room temp water for the dunk and started the boiling right away so I didn't see the need for mash out with this technique.

It works well. I'm really geeked about it. This system has allowed me to do AG batches without buying all kinds of extra equipment. My kettle is beg enough I really can't see myself ever going to a gravity feed system.

 

[wilserbrewer]

Yes, I have heard in theory two equal volume runnings will maximize efficiency, so with 3 gallons reserved for a sparge you should be close to 50/50.
Cheers!

 

[cervid]

Thanks for the bags by the way. I ripped a tiny hole in it on the thermometer when raising out, which kind pissed me off, but not too big to let grain through I think. I guess I'll just stitch over it if it's an issue. Obviously that was an issue on my end.

 

[ArcLight]

>.I think it does matter though. Having a really thin mash will raise the ph of the main mash, potentially extracting tannins.

This is not going to be a problem unless you have hard water.
The majority of BIAB brewers don't even sparge they mash thin and raise the bag. They may use 7.5 gallons for 10 pounds of grain (a 3:1 ratio) and not have tannin problems.

I like to hold back 2-3 gallons for the dunk sparge, enough so that the grain is submerged and there is some extra liquid and I can mix it around. I estimate this increases my efficiency by 10% (ex: 70 -> 77).

 

[RM-MN]

To extract tannins you need a pH over 6.0 and temperature over 170. If you don't mash out, your grains never get that hot.

 

[jCOSbrew]

For me, BIAB is about simplicity. Single vessel, no mash out, no sparge, etc.
If your process is repeatable and your efficiency is reasonable (>70%) than don't get too fixated on the efficiency number.

 

[cervid]

>.I think it does matter though. Having a really thin mash will raise the ph of the main mash, potentially extracting tannins.

This is not going to be a problem unless you have hard water.
The majority of BIAB brewers don't even sparge they mash thin and raise the bag. They may use 7.5 gallons for 10 pounds of grain (a 3:1 ratio) and not have tannin problems.

I like to hold back 2-3 gallons for the dunk sparge, enough so that the grain is submerged and there is some extra liquid and I can mix it around. I estimate this increases my efficiency by 10% (ex: 70 -> 77).

I do have incredibly hard water and I use Bru'n Water to figure my water chemistry and ph because it is so bad... Even with my water diluted with Distilled and built back up with salts it is still telling me 5.5, which is fine, but I like the idea of mashing in 5 gallons which is 5.3. So, whether or not your water is hard, the mash ph changes a lot.

Regardless, holding 3-4 gallons to dunk sparge (in my case, or dump sparge) is the best of both worlds.

I agree about repeatability and not worrying about the numbers, but the way I see it is one, I shoot for the lower ph this way (I'm not getting a tester anytime soon and the strips are meaningless). Two, I pretty much never have to worry about being able to fit a mash in my 42 qt pot with a large grain bill, and three, I might get that little bit of efficiency out of it.

So, that's my logic and why I started BIAB that way. I don't want to have to go back and forth between calculators to figure out, 'can I mash it' or not. I used this one: http://www.simplebiabcalculator.com/ for water temp and water volume for the amount of grain, and it's a one stop reference.

I build the water on Bru'n Water the night before, add salts, let it sit, then pour off what I want to dunk in, can't get any easier for me. We use Chlorine, not chloramine, so this makes sense to me, and I don't have to use Campden.

I like it to be easy, but I'm not exactly a cowboy either. I am going this route because it costs me hundreds of dollars less to do all grain over buying a mash/lauter tun and possibly a HLT, not really for ease, but as I see yesterday that is a really nice advantage of this system. I can't see myself adding more kettles, a tun and burners.. I can do this stovetop with a heatstick and it's awesome.. I think it was single digits when I brewed this batch, so it's nice being able to do it in a robe if I wanted to..

 

[cervid]

To extract tannins you need a pH over 6.0 and temperature over 170. If you don't mash out, your grains never get that hot.

I didn't realize it took both, I thought just the high ph was enough.. So, not sparging with 190 degree water, and not doing a mashout... Does that make ph a moot point entirely?

I brew a fair amount, so the efficiency increase is nice and it's easy to have my smaller pot right next to the kettle to dunk in. But, mainly, my pot isn't filled as much when mashing and I can heat that 5 gallons a lot faster and better without the heatstick on my glasstop stovetop. So, those reasons made it easier for my system.

Thanks for the info and replies.

 

[RM-MN]

I didn't realize it took both, I thought just the high ph was enough.. So, not sparging with 190 degree water, and not doing a mashout... Does that make ph a moot point entirely?

I brew a fair amount, so the efficiency increase is nice and it's easy to have my smaller pot right next to the kettle to dunk in. But, mainly, my pot isn't filled as much when mashing and I can heat that 5 gallons a lot faster and better without the heatstick on my glasstop stovetop. So, those reasons made it easier for my system.

Thanks for the info and replies.

Not exactly. The enzymes have a range of pH that they prefer to work in but at least you won't have to worry about extracting tannins. By the time your pH gets high enough to extract tannins at mash temps, I don't think you are mashing anymore.

 

[PRE66_6TART]

I think it does matter though. Having a really thin mash will raise the ph of the main mash, potentially extracting tannins.

I just meant that getting less efficiency from the thicker mash doesn't matter, since you make up for it with the sparge. I still think the ph difference is important.

 

[PRE66_6TART]

I didn't realize it took both, I thought just the high ph was enough.. So, not sparging with 190 degree water, and not doing a mashout... Does that make ph a moot point entirely?.

I think having the right ph has other benefits besides avoiding tannin extraction. I also get lots of "grain dust" that escapes the bag and ends up in my boil so I think that could still be a source of tannins if the ph is off.

 

[cervid]

Thanks for the info. Consistency is big, so I'll keep doing it how I did at first and adjust in a couple months after a dozen batches or so if I think somethings off.