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Biab:dunk Sparging In Second Urn.

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Truman42

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I currently do BIAB in an 18 litre urn and dunk sparge in a bucket, usually once pre boil and a second time during the boil to allow for evap loss.

I have acquired a second urn and was thinking of revising my process and would appreciate some advice on this.

Here is my revised procedure based on what Ive read and learnt on here

Mash in urn one.

Have urn 2 approx half full with water set at a suitable temp for sparging (What would that be exactly?? 80C???)

Mash out and pull the bag, let it drain then lower it into urn two and stir the grains. After ten minutes drain off into a 1 or 2 litre jug and recirculate to filter and once it runs fairly clear add to urn one for pre boil top up.

Then leave the remaining wort in urn 2 with the bag and the grain still in there until about 30 mins boil time left and drain into the kettle to top up for evap loss. (Or I could add extra water from a kettle into urn two if I need to top it up after the first sparge)

So would this procedure have any benefits or problems over a standard "green" bucket dunk sparge?
 

cozmocracker

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i also BIAB using two urns, a 40 ltr one which i use to mash in and boil in, i use the 2nd urn (a 20 ltr one)as a HLT, after mash i lift the bag and then pour the sparge water from the second urn through the bag, i usually aim for 73 to 76 degrees. i hope this helps.
 

Truman42

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Can you explain what you mean by pour the water through the bag? Do you put the bag in the second urn then drain the water through it?
 

the_new_darren

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Im confused,

If you have two urns then why do you need to use a bag?

mash/lauter in first urn, drain to second urn and then boil!!

tnd
 

cozmocracker

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i suspend the bag over the urn (i have a pulley system in place) and then use a jug to pour the water through the bag.

i use the bag because i dont have a false bottom or any other means to keep the grain out of the wort, and the 2nd urn isnt big enough for the boil.

i hope that clears things up abit.
 

the_new_darren

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Can you mash in the other urn? If so put a piece of slotted copper tube at the bottom of it and you can dump the bag.

tnd
 

stux

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I use a 98L and 50L pot to do 60L (into fermenter) BIAB batches with a dunk sparge in the 50L pot. I reckon I could do 80L batches to, but I only have a 60L fermenter ;)

The way I do it is to put about 25L in the 50L pot (can vary if the grain bill is big). I boil the water in the 50L pot with the lid, while I'm mashing with about 70L in the 98L pot. Once it reaches boiling I cut the heat. It will cool to about 80-85C by the time I finish my main mashout, and will drop back to mashout temps once I put the drained grain in.

Anyway, I ramp the main mash to mashout, then pull the bag and drain, and begin heating the main pot to boil. Then I lower the bag into the 50L pot, tie my grain bag draw string around the lip of the pot and use my potato masher to rehydrate the grain. Careful, the grain takes up a lot of volume until you rehydrate it... start from the bottom!

I use the masher to periodically agitate the grain, and after about 10 minutes I pull the bag. Then I start the second pot heating if I'm going to be making boil-time additions.

Otherwise I just add the entire contents of the sparge pot back to the main pot and then when pot comes to the boil I start my boil.

I've been getting 85-93% efficiency into the boil with this method, and 80-85% efficiency into the fermenter

My CE BIABcalc can be used to predict the volumes and results, as this is the sparge process it models.

1_Ready_for_Dunk_Sparge.jpg
 

glenwal

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Why not get a 2nd bag and do two half batches, and then combine in the fermenter. Then you don't have to worry about sparging because you'll be doing normal biab instead of maxibiab.
 

Truman42

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I use a 98L and 50L pot to do 60L (into fermenter) BIAB batches with a dunk sparge in the 50L pot. I reckon I could do 80L batches to, but I only have a 60L fermenter ;)

The way I do it is to put about 25L in the 50L pot (can vary if the grain bill is big). I boil the water in the 50L pot with the lid, while I'm mashing with about 70L in the 98L pot. Once it reaches boiling I cut the heat. It will cool to about 80-85C by the time I finish my main mashout, and will drop back to mashout temps once I put the drained grain in.

Anyway, I ramp the main mash to mashout, then pull the bag and drain, and begin heating the main pot to boil. Then I lower the bag into the 50L pot, tie my grain bag draw string around the lip of the pot and use my potato masher to rehydrate the grain. Careful, the grain takes up a lot of volume until you rehydrate it... start from the bottom!

I use the masher to periodically agitate the grain, and after about 10 minutes I pull the bag. Then I start the second pot heating if I'm going to be making boil-time additions.

Otherwise I just add the entire contents of the sparge pot back to the main pot and then when pot comes to the boil I start my boil.

I've been getting 85-93% efficiency into the boil with this method, and 80-85% efficiency into the fermenter

My CE BIABcalc can be used to predict the volumes and results, as this is the sparge process it models.

View attachment 53002
This is exactly what I want to do but because I use 2 x 18 litre urns could only drain some of the sparge urn's water into the kettle pre boil and the rest during the boil, which I suppose would be dependant on how much water I can fit in the sparge urn with my wet grain bag.
But is there any reason why I cant just leave the bag in the sparge urn, drain what I can into the kettle to top up for pre boil, then either add some more water to the sparge urn if required from a 2 litre kettle, or just leave whats left sitting there until needed during the boil?
Would having the grain bag sitting in the water for an hour or so during the boil cause any problems?
 

stux

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This is exactly what I want to do but because I use 2 x 18 litre urns could only drain some of the sparge urn's water into the kettle pre boil and the rest during the boil, which I suppose would be dependant on how much water I can fit in the sparge urn with my wet grain bag.
But is there any reason why I cant just leave the bag in the sparge urn, drain what I can into the kettle to top up for pre boil, then either add some more water to the sparge urn if required from a 2 litre kettle, or just leave whats left sitting there until needed during the boil?
Would having the grain bag sitting in the water for an hour or so during the boil cause any problems?
Not sure on if its bad or not, but the problem is if you just drain out of the tap you might find that the wort won't drain from grain as efficiently as if you had suspended/squeezed it. In the past when I've used buckets and the like to drain bags its never worked as well as actually suspending the bag

Mind you, if you're draining out the tap of the urn... you are actually doing a normal mash tun batch sparge... just with a fabric manifold ;). There will be large amount of loss, and loss is loss.
 

Bribie G

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A 40L urn will do a nice full-volume BIAB with no sparging necessary.

Split that in 2 for your two 18L urns and you should still be able to do a full volume brew without sparging by dividing the grain bill and just do a simple BIAB in each urn - with perhaps a slight decrease in efficiency as a bit more sweet wort will be trapped in the spent grain.

Just get another bag. If you are concerned about loss of efficiency, then just do a bit of a bucket sparge with each grain bill, and pour the yeild back into each urn and boil for a bit longer to get the wort volume down.

Divide and conquer.

:icon_cheers:
 

stux

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So, you would strike with about 13.5L, and have 10L of sparge in your sparge urn.

With a 4.5KG grain bill that'd give you a 16.7L (or so) mash, and then when you dunk sparged another 16.7L mash.

Interestingly, this gives you a near 3:1 liquor:grain ratio....

When you pull your dunk sparge you can then add as much back as you feel comfortable... 7L? and then add the remainder into the boil as you feel comfortable?

As mentioned before... another way is to just run two biabs simultaneously... the benefit is you get to double your evaporation rate and avoid a lot of dicking about.

....

If I were you I'd keep my eye out for a 40L urn ;)
 

Truman42

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Ive considered doing a split batch in both urns and already have another bag but was a little hesitant as I thought it might be too much to handle on brew day while still learning.

But having said that Im now 7 Biabs in and a bit more confident so could give it a crack I suppose.
 

stux

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Ive considered doing a split batch in both urns and already have another bag but was a little hesitant as I thought it might be too much to handle on brew day while still learning.

But having said that Im now 7 Biabs in and a bit more confident so could give it a crack I suppose.
What Wattage are the urns? will it they fit on a single circuit... or do you have multiple?

His and Hers Urns ;)
 

Truman42

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What Wattage are the urns? will it they fit on a single circuit... or do you have multiple?

His and Hers Urns ;)
They're both 2400 watts. I haven't tried them both together as I still need to do some repairs to my second urn but I'm guessing I will have to plug them into separate circuits. Hopefully one in the garage and one in the laundry as the door opens into the garage so they would be close to each other.
 

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