Another batch sparge question

[MrFancyPlants]

I am biab in a 5G pot with 11-12 pounds of grain. How many times can I dunk/batch sparge my bag of grains. I know the right answer would depend on water chemistry, but I haven't done a ph test yet. I've had pretty good luck dunk sparging once in another 5G kettle (even got OG up to 1.090), but wondering if I could sparge a second time since I am brewing a big batch this time around. My recipe has ~10% specialty malts which I hear can help keep the ph in range. Would cool water on the second sparge reduce tannin extraction?

 

[MagicMatt]

First it'd help to clarify whether you're talking about dunking or batch sparging. You use these terms interchangeably, but they are not necessarily the same thing. Batch sparging is the addition of new water to the drained grains. Dunking is usually just re-submerging the grainbag in the sweet wort (mash liquor).

Note that with a normal 60 minute mash, your mash liquor will generally contain most of the sugar you will get from the grain. In fact, dunking your drained grains back into this will likely actually reduce the sugar content as some gets reabsorbed into the grain themselves.

When I BIAB, I don't sparge at all. Mash as usual, pull out the grain bag and set it in a colander over a bowl, and squeeze/strain the liquid out of the grains and into the collection bowl, then add that extra liquid back to the pot. I think most BIABers are not sparging these days.

 

[MrFancyPlants]

Thanks for the thoughtful reply. I mash in one 5 gallon kettle and put the bag in another 5g kettle and fill with fresh water. Then I stir the contents into the water and lift the bag back out. That's why I am calling it a dunk/batch sparge. I had to start doing this in order to get my efficiency up to a manageable level given my small kettle size.
To complicate things (and sometimes make a mess) I actually do this with both kettles and two bags. Mash two ~11# grain bags in 2x5G kettles. Lift bags out. Combine first runnings into one kettle and set to boil. Then "dunk" sparge both bags in second kettle. I do mix some of the wart back and forward so that I can evenly divide the bittering hops.
What I'm wondering is if I can go for a third round of this to increase my efficiency. I can get about 8G of 1.090 wart this way, but after boiling/trub loss I am only getting about 5G of (quite tasty) beer. For my batch this weekend, I am trying to fill a 15.5G Sankey for a friends wedding, so I'll be topping off the fermentor with water to bring the wart down to 1.040 OG. I'm expecting 10 or 11 G of 1.040 wart, but if I could get just a couple more G then I wouldn't have to top off the Sankey with all of my high gravity beer that is ready to drink now.

 

[MagicMatt]

Ah I see what you're saying now. I'm not sure how another round of dunking in fresh water would work in terms of increasing efficiency. I would think that it would extract more sugars, but obviously to a lesser extent than the first dunk. You may only end up with say 1.010 wort from the second dunk, which when added to your main kettle will mean you'll just have to boil a bit longer to evaporate the extra water added. Sounds like it could work, but I don't have any experience with this sort of thing.

 

[MadHomebrewer]

I did this on a one gallon scale and it worked out well. Increased my efficiency from my previous batch. In stead of putting all you water in one pot you, you hold some in a second pot. I heated my spare water to 170. Stir rinsing your grains then combine your pots. View attachment ImageUploadedByHome Brew1439574797.658742.jpg

 

[MrFancyPlants]

That looks like what I am doing, but can you rinse the grains twice? As pointed out, I'm not sure if it is worth risking tannins for an additional (in my case) 4G of 1.010 wart. I've done party guile before and made a decent braggot out of the second runnings at 1.020 (doubled to 1.040 with honey), maybe I should try that with the third runnings before I risk including any potential off flavors from the third runnings in the big batch.

 

[doug293cz]

That looks like what I am doing, but can you rinse the grains twice? As pointed out, I'm not sure if it is worth risking tannins for an additional (in my case) 4G of 1.010 wart. I've done party guile before and made a decent braggot out of the second runnings at 1.020 (doubled to 1.040 with honey), maybe I should try that with the third runnings before I risk including any potential off flavors from the third runnings in the big batch.

Yes, you can dunk sparge twice, and it will extract a little more sugar, but much less than the first sparge. Another way to improve sugar extraction is to squeeze the bag very aggressively prior to the first sparge, and again after the sparge. The amount of grain absorption plays a big role in efficiency.

For example, with a 13 lb grain bill to generate 7.25 gal pre-boil, with a single batch sparge:

• For a grain absorption of 0.12 gal/lb, max efficiency = 85%
• For a grain absorption of 0.05 gal/lb, max efficiency = 92%
• For a double sparge at 0.12 gal/lb, max efficiency = 88%

Brew on

 

[locolorenzo22]

I get consistent 75-80% efficiency using a 8 gallon pot on a double gas burner on the stove. I mash with 4 gallons of water, then put into 2 buckets put together, where one has a whole bunch of holes in it (seriously took 1.5 hours to make all the small holes) set inside another bucket. Dump my sparge water on top (heated to 169). then let sit for 10 minutes to drain, then dump into wort and boil per recipe. Works great.

 

[jtratcliff]

Dunking is usually just re-submerging the grainbag in the sweet wort (mash liquor).

Does anybody else use this definition of dunk sparge?

I've always taken a dunk sparge to be dunking the grain bag in a separate pot of sparge water...

i.e. almost completely analogous to a batch sparge...

Is my understanding incorrect? Do I need to update my terminology?

Or is it the difference between "dunk" and "dunk sparge" that is the hiccup?

 

[doug293cz]

Does anybody else use this definition of dunk sparge?

I've always taken a dunk sparge to be dunking the grain bag in a separate pot of sparge water...

i.e. almost completely analogous to a batch sparge...

Is my understanding incorrect? Do I need to update my terminology?

Or is it the difference between "dunk" and "dunk sparge" that is the hiccup?

I have seen one poster talk about dunking the bag back it the wort, and claiming they did it to improve efficiency. :smack:

I've always thought dunk and dunk sparge were synonymous, as there is no rational reason to dunk the bag back into the wort.

Brew on

 

[Kharnynb]

I do a similar system with a batch sparge in my fermenter with hot water (don't have a second large enough kettle).

It took my efficiency up from mid 60 to 72%, I doubt a second sparge would do much extra though.

 

[MrFancyPlants]

I think dunk and batch are synonymous. I mean bags don't really go with vorloff that I know of. I'm going to try the third runnings out in a different carboy for "quality control." Unfortunately, only the 2 6G carboys fit in the kegorfermorator.
Amorita's Superfrajicagalistik Bitter is tasting fine in the worlds messiest brew shed. I better get to scrubbing those carboys for my shotgun 5G kettle gas range brew session tomorrow.

 

[MrFancyPlants]

My 3rd Running came out to only 1.012, which is good that it is over the line for the 1.010 threshold that I have read can indicate tannin extraction. I added some honey and will add some lactose for a milk and honey braggot. I eyeballed the honey addition at about a 1.5#.. well it was the rest of my bottle of honey into the 3G of third runnings. Because more than half of the fermentables are honey and I probably used too much hops for the boil (1 ounce glacier ~6aa), I decided the lactose could probably help bring this back into the realm of drinkability along with some dry hop. I'll try to get the final gravity up to 1.010 with the lactose addition at bottling.