Fly sparge with drained MLT?

[BrunDog]

Hey brew science minds... I have worked hard to make a fly sparging system that appropriately feeds water to the top of the grain bed while simultaneously draining liquid off at a slow rate. This is the goal to fly sparging as so many resources have dictated.

Batch sparging requires draining of the MLT before adding sparge water.

So my question is... What is wrong with fly sparging where you would fully drain the MLT, then sprinkle hot water over the "dry" grains? This is common in BIAB practice for those who sparge, and I remember successfully sprinkling water over grains in a colander during my first homebrew trials.

Is it a compacted mash, tannin extraction, or channeling that is the concern? Seems like fly sparging would be infinitely easier if it were done this way. Thoughts?

 

[eluterio]

Good question never thought to ask it seems like a slower way to batch sparge. Not sure what impact it would have.

 

[Gavin C]

My guess is that the added sparge water would just channel right through the moist grain bed in a conventional MT. Lautering efficiency would take a nose dive.

Gravity and the path of least resistance.

The negative effect of the channelling would just increase as the pour over sparge proceeded as chanels are widened by the flowing water.

 

[doug293cz]

Interesting idea. Acidify the sparge water to a pH of 5.8, and you won't have to worry about tannin extraction.

As Gavin says, channeling would be the main concern. You would need to distribute the sparge water very evenly over the grain bed, and feed very slowly. A bucket with lots of very small holes all across the bottom might make a good sparge water distribution manifold, or a piece of filter paper that completely covers the grain surface and fits tight around the edge might also work. Probably other ways to do it as well. Sounds like a neat experiment. Why not give it a try? You will make beer.

Brew on

 

[trentm]

Fly sparging is considered the most efficient method of sparging because the upper portion of the mash is maintained in a fluid state, while the bottom few inches pack to form a filter bed. Maintaining the fluid state allows for the sugars to dissipate out of the grain particles into the liquid then flow through the filter (packed portion) to clarify and remove any solids. However, with small batches and an efficient system, fly sparging can be more efficient than necessary regarding lautering. In my 12 gallon system it is necessary to stop the sparge after ~11 gallons has been collected and top up liqueur is used to reach the full boil volume (14 gallons). Since homebrewers can achieve good efficiency on small batches, numerous methods have been contrived to make the process faster. Just remember there is more to sparging than just good efficiency, it may also important to collect nice clear wort that's free of any grain solids. The latter may be especially important when brewing pale delicate beers that allow any astringency to show through.

 

[BrunDog]

Good point! Draining the MT may render the grain "filter" non-functional.

 

[BeardedBrews]

it seems like a slower way to batch sparge

I guess I'm having a hard time seeing past this point. Would there be an advantage in your system to fully draining the MLT before starting the sparge? Or is it more a question of "what is the risk of exposing the grain bed by draining the MLT too fast"?

 

[eluterio]

I guess I'm having a hard time seeing past this point. Would there be an advantage in your system to fully draining the MLT before starting the sparge? Or is it more a question of "what is the risk of exposing the grain bed by draining the MLT too fast"?

In thinking about this, if I were to try this it would go as follows;

would drain out the mlt
slowly sparge with 170 degree water
leaving the valve open to drain wort

This to me would take the same amount of time as it would doing a fly sparge.

I don't think there are major risks exposing the grain bed but people above have listed the possibilities of lack of efficiency through channeling. Your MLT gain bed would most likely need to be set again or you can use a hop sack at the end of your drain tube to catch what ever grains make it through.

Through my reading and doing, fly sparge, batch sparge no sparge will get you the end result WORT. You will have different efficiencies with each one but can be compensated by adding or subtracting lbs of grain.

I hope this kind of makes sense in a long worded answer to say yes you can do you it.

 

[McKnuckle]

With sparging techniques, I always visualize the metaphor of rinsing soap from one's body after lathering up in a bathtub.

A batch sparge is like draining all the soapy water out as fast as possible, then refilling the tub with clean water, and doing it again really fast while you continue to lie there.

A fly sparge is like draining the soapy water out slowly, while simultaneously dribbling clean water from an overhead shower, and keeping your body submerged.

BIAB (no sparge) is like taking the bath in twice as much water, then just standing up and getting out of the tub. And optionally splashing a cup of clean water over yourself afterwards.

So here, you're talking about draining all the soapy water really quickly, then dribbling clean water from an overhead shower while you lie there - mostly dry. I'm not sure that would be satisfying...

 

[BrunDog]

Funny metaphor! Not sure about the satisfaction part, but spot on otherwise.

The point would be that this would be a simpler form of fly sparging. No input/output matching needed. Faster time to start your boil in multi-vessel systems because the first bolus of wort is available quickly and can be started heating.

Heck, *maybe* you would get better efficiency as you drain off all the sugars at first, rather than mixing with water on the way out?

 

[jddevinn]

A mechanical issue I would see is most of our small scale mash tuns don't bottom drain, they use a dip tube to get under the false bottom. So when running the sparge the system would drain almost everything from the mash tun, then completely stop draining until there is enough water to cover the high portion of the dip tube (assuming a non priming pump) then drain out, then repeat.

Is this just a theoretical or did the autosparge, flow meter and proportioning valve not work as intended?

 

[Bobby_M]

Effectively it's both less efficient than batch sparging AND fly sparging but would take more time than a batch and slightly less time than fly. The downside is that you risk oversparging (pH drift) the most with this technique due to the inevitable channeling that will occur. See, sparging is often correlated with rinsing and the word rinsing is too closely associated with a showerhead. It's not really like that. Fly sparging is more like diffusion within a vertical gradient. That sounds like a lot of bullsh@t but if you picture a 1cm tall slice of the mash, the wort one step above is lower gravity and one step below is higher gravity. As those "plates" of wort move down, they encounter more sugar on/within the grain and it diffuses out creating a new higher SG and on and on until it gets to the false bottom.

In the proposed scenario, this is only happening on the sparge water droplet level and you have no way of ensuring that many droplets are not taking the same path through a terribly oversparged path of grain.


And no, I don't like the sprinkle through version of BIAB sparging either. For my money, a dunk sparge is better in every way.

I'll ask a followup. What issue does batch sparging cause that this technique would solve?

 

[BeardedBrews]

No input/output matching needed. Faster time to start your boil in multi-vessel systems because the first bolus of wort is available quickly and can be started heating.

I know the Auto-Sparge from Blichmann was mentioned earlier, doesn't that address the flow-matching concerns at least to some extent?

http://www.ebay.com/itm/STAINLESS-A...ce-/181879835654?_trksid=p2141725.m3641.l6368

 

[jddevinn]

I know the Auto-Sparge from Blichmann was mentioned earlier, doesn't that address the flow-matching concerns at least to some extent?

http://www.ebay.com/itm/STAINLESS-A...ce-/181879835654?_trksid=p2141725.m3641.l6368

I mentioned it earlier because I have followed BrunDog (OP's) build thread and he is using a combination of this and other controls with a BCS currently to sparge. I like the solution and want to know if there are any issues.

Currently I use panel mounted flow meters (not mounted in a panel) to set my flow rates. Works a lot better than guessing!

 

[BrunDog]

A mechanical issue I would see is most of our small scale mash tuns don't bottom drain, they use a dip tube to get under the false bottom. So when running the sparge the system would drain almost everything from the mash tun, then completely stop draining until there is enough water to cover the high portion of the dip tube (assuming a non priming pump) then drain out, then repeat.

Is this just a theoretical or did the autosparge, flow meter and proportioning valve not work as intended?

Very true and a good point. The liquid rising above the false bottom would likely disturb the grain bed and might create more cloudy wort.

No, this is theoretical. My electronic autosparge is working great so far. I think I asked because of all my efforts and learnings to build a matching system. Eliminating it would be easier for many system builders if it were a valid method.

 

[BrunDog]

I know the Auto-Sparge from Blichmann was mentioned earlier, doesn't that address the flow-matching concerns at least to some extent?



http://www.ebay.com/itm/STAINLESS-A...ce-/181879835654?_trksid=p2141725.m3641.l6368

I use an electronic system, but yes, you are correct that a mechanical solution like this solves the matching. Nonetheless it does add complexity, cost, etc. This no-matching concept would be easier for new builders to do, at least in theory!

 

[BeardedBrews]

It may be worth testing the accuracy of those cheap-o DC high temperature pumps for this application. It should be easier to automate the pump speed, and at this point in the brew process you aren't dealing with big chunks in the liquid flow paths.

 

[jddevinn]

Very true and a good point. The liquid rising above the false bottom would likely disturb the grain bed and might create more cloudy wort.

No, this is theoretical. My electronic autosparge is working great so far. I think I asked because of all my efforts and learnings to build a matching system. Eliminating it would be easier for many system builders if it were a valid method.

Yes it would make it easier. I used to constantly babysit and adjust to match the flow rate. The rotometers I'm work surprisingly well (for using ball valves to set flow rather than a control valve), I can set them to 0.2gal a minute set a timer for a few minutes before my calculated boil volume and its very close. Bought the rotometers on ebay....the QD on them cost about 2x as much as they did

I would much prefer something automated. If I ever scale up it will be with at least the level of automation that you have:rockin:

 

[BrunDog]

Thanks. If I get the itch I might just do an experiment to see the efficiency difference. Ideally it would be compared to a batch sparge but I am not sure I am that ambitious.

 

[jddevinn]

Thanks. If I get the itch I might just do an experiment to see the efficiency difference. Ideally it would be compared to a batch sparge but I am not sure I am that ambitious.

If you bother to do this.... break out the pH meter would you and measure the difference in the two methods, both the total in the boil kettle and at a couple points during the "sparge"

 

[BrunDog]

Good idea.