Alternate Fly Sparge Method Question

[HardyFool]

Hey all,

I've just installed a proper false bottom into my mash tun, and as I already have a HLT and sparge arm, I've started fly sparging my mashes. Now, as I'll be shortly purchasing a nice little SS pump, I've begun to think about recirculation during the mash, and potentially during the sparge. But here's the catch: I am a young brewer (22, don't worry), and as I live in my parents' house, I'm restricted to one gallon batches. So continuous sparging has proven difficult, as the drip rate appropriate to continuous sparging causes my "wort aerator" sparge attachment to produce a single drip in the center of the tun.

Now, any sane person would say, "why not just BIAB every beer, and ditch the false bottom? For that matter, even if you wanted a higher efficiency for the odd high gravity beer which could pose volume constraints on your tun, why not batch sparge?" But I brew primarily for the engineering challenge it poses, and my goal is to hit 90% efficiency with my one gallon setup, so until I'm convinced that it's wildly impractical to continuously sparge, I will pursue that goal.

So, the idea: instead of simply adding sparge water to the top and hoping it effectively rinses the grain bed in one pass, why not take a note from our distilling friends, and fabricate a "forced reflux" HLT, wherein a pump constantly recirculates the wort, and a valve is introduced downstream of the pump to "bleed" a small portion of the wort continuously, while fresh sparge water is added to the top of the tun to replace the displaced, bled wort? This would allow me to produce a very even drip pattern atop the entire grain bed, but the efficiency of rerunning the wort through the grains, let alone the efficiency of quickly vs slowly running the sparge water past the grains, are things I do not understand well enough to know if this is a very good idea, or a very bad idea. I've never heard of it being done, but that's possibly because it would be very impractical for anything above a few gallons

The logistics of this are mercifully simple, my questions are this: is this more efficient than batch sparging? Would recirculating already sugar-rich wort back through the grain bed kill the efficiency of fly sparging for some reason? At what point do the grains "catch" more sugars, if that's even how that would work, than they leech into the wort? In short, the absurd impracticality of this endeavor aside, would this be more or as efficient as batch sparging? Also, the alternative to achieve a uniform sparge spread would be the drill very small holes in a rotating or non-rotating piece of small ID soft copper tubing, which I have a length of lying around - I will certainly be trying this solution

Thanks in advance for your feedback!

 

[doug293cz]

Recirculating during a fly sparge will lower your efficiency. With sparging (either continuous or batch) you want each bit of water to pick up the maximum possible amount of sugar before the water leaves the grain bed. The less sugar there is for the next bit of water to pick up, the better your efficiency will be. By recirculating the sparged wort, you are putting sugar back into the grain bed, so that the additional sparge water will have more sugar to try to rinse out. That's exactly the opposite of what you want.

Brew on

 

[kombat]

Yeah, as mentioned, this is a bad idea. You want the water in the upper portion of the mash to be as clear as possible, because it means there are almost no sugars left in the grain (i.e., they've all been successfully rinsed out, maximizing efficiency). When fly sparging, the clear water being added to the top acts as a "piston," pressing the sugar-rich water down through the grain bed, and maximizing extraction. You would be reintroducing sugars to the top of the grain bed, where they would have to be repeatedly picked up by sparge water, and dragged all the way through the grain bed again.

 

[Simonh82]

It may not be a good idea during the sparge but could help during the mash. Many of the commercial single vessel systems, like the Grain Father operate on the basis. The main difference is that they have an internal heating element and controller which maintains the mash temperature as the wort is recirculated. If you are after an engineering challenge this may be the way to go.

If you recirculated the mash at a stable temperature and then switched to a fly sparge afterwards, I bet your efficiency would be fantastic.

Saying that. I think 90% with a 1 gallon set up is certainly ambitious.

 

[bonecitybrewco]

Solubility of maltose at 151 is approximately 200g per 100g of water and only goes up from there.

If I am understanding, this would essentially just be fully saturating the solution, depending on re-circulation time and a few other factors.

For example, if you were to do a full volume mash (no sparge), and recirculate, you would IN THEORY be able to fully saturate the solution and extract ~100% of the sugars. Obviously this would result in an extremely high mash efficiency. Unfortunately, this is only one aspect of brewhouse efficiency, which is what I think you are chasing with that 90% number.

Not sure how it would work with fly sparging though, as you are constantly introducing higher temp water from above and the grain bed is pretty much set at that point. However, if you were able to keep your grain bed completely in suspension (introducing sparge water from below is one possible idea), this may serve to do what you are trying to achieve. Then again, this sounds much like batch sparging instead of continuous.

I can't be too specific, but similar processes (recirculation of a saturated solution) are done in certain salt refining processes. Larger vessels, higher temperatures, different atmospheres, but all for purpose of higher saturation and precipitation of impurities.

 

[Redlantern]

So - mash, introduce X quantity of water for sparge, bleed slowly, recirculate the rest, introduce clean water to replaced bled volume?
Remember, if your mash temp gets too high, you denature the enzymes. I believe your beta amylase begins to denature at 158°F, so you begin impacting the fermentable sugar quantity. If sparge is at 168°F, then you begin to shut down beta.

My first question is - where is your efficiency lacking the most? What factors are keeping you where you are?

I would experiment with milling the grain better first.

In one gallon batches, a small hand cranked mill would be; fast, cheap, easy to control, and less involved. For engineering, try the cheaper, easier solutions first. In absence of success with that, move on to more elaborate ones.

My money is that a proper crush will give you a big jump in efficiency. It may also improve repeatability.

 

[Redlantern]

If you want to get really crazy - see if there are any food grade surfactants that do not negatively affect starch to sugar conversion.


http://garudaint.com/product.php?id=15


Seems that reducing water tension would help - but I have zero idea if that is possible for a successful beer.

 

[Bobby_M]

Putting any runoff wort back on top during the sparge is a loss of efficiency. The more you put back, the closer to batch sparging you get with none of the pH stability or time saving benefits of batch sparging.

The sprinkling effect of most sparge mechanisms is completely not necessary. The only good it does is not drill down into the mash but at the flow rate you'd be going for, a single drip is not a problem. You'll be leaving 1-2" of water on top of the grain anyway.

 

[kombat]

The sprinkling effect of most sparge mechanisms is completely not necessary. The only good it does is not drill down into the mash but at the flow rate you'd be going for, a single drip is not a problem. You'll be leaving 1-2" of water on top of the grain anyway.

Indeed. I occasionally fly sparge, and I don't even have a sparge arm. I just lay a sheet of aluminum foil over top of the grain bed, and punch a bunch of small holes in it (with my thermometer probe). When it's time to fly sparge, I just run the return tubing from the pump back into the mash tun and lay it on the foil. The wort gets pumped back out, onto the aluminum foil, where it (presumably?) gently finds its way down through the small holes, trickling back into the grain bed.

 

[HardyFool]

Hey all, first of all, thanks for all the feedback! I posted for exactly that, and I'm grateful to you all.

Re: doug293cz and combat, I suspect that you guys are right, and when I ran this idea past the head brewer at MacLeod Ale in Van Nuys (shameless plug), he said the same thing.

Re: Simonh82,

It may not be a good idea during the sparge but could help during the mash. Many of the commercial single vessel systems, like the Grain Father operate on the basis. The main difference is that they have an internal heating element and controller which maintains the mash temperature as the wort is recirculated. If you are after an engineering challenge this may be the way to go.

If you recirculated the mash at a stable temperature and then switched to a fly sparge afterwards, I bet your efficiency would be fantastic.

A true Rims system, or better yet, a recirculating loop with steam injection (for one gallon? Am I mad?) is high on the list of pending upgrades, as I want to be able to step mash for lagers and sours, and those finicky deutschen Bier in general. As I'll mention in a second, it is but one of a handful of upgrades that I intend to install to raise my mash efficiency

Re: Bonecitybrewco

Solubility of maltose at 151 is approximately 200g per 100g of water and only goes up from there.

If I am understanding, this would essentially just be fully saturating the solution, depending on re-circulation time and a few other factors.

For example, if you were to do a full volume mash (no sparge), and recirculate, you would IN THEORY be able to fully saturate the solution and extract ~100% of the sugars. Obviously this would result in an extremely high mash efficiency. Unfortunately, this is only one aspect of brewhouse efficiency, which is what I think you are chasing with that 90% number.

Not sure how it would work with fly sparging though, as you are constantly introducing higher temp water from above and the grain bed is pretty much set at that point. However, if you were able to keep your grain bed completely in suspension (introducing sparge water from below is one possible idea), this may serve to do what you are trying to achieve. Then again, this sounds much like batch sparging instead of continuous.

I can't be too specific, but similar processes (recirculation of a saturated solution) are done in certain salt refining processes. Larger vessels, higher temperatures, different atmospheres, but all for purpose of higher saturation and precipitation of impurities.

Thank you thank you thank you! First of all, yes, you've keyed into the point of the technique - I want to be drawing a slow trickle of wort from a fully saturated solution, and I suspect I'll be spending the next few weeks researching this topic. Your idea to keep the grains in suspension is clever, and likely what I'll end up doing if fly sparging nets me anything below, say, 85% mash efficiency. Speaking of, yes, that's the 90% I mean - I simply want to be able to pull as much sugar from my grains as I can without pulling silicates and tannins, which to me would signal the success of my design. I already carefully build water from distilled (you only need ~$3 of distilled water for a one gallon batch), and the last two mashes have read ~5.4 pH throughout, so I don't suspect water chemistry to be hurting my mash efficiency. More rests could help, but I'm constrained to single infusions at the moment (RIMS or steam injection pending). In any case, I will certainly starting looking into ways to maximize wort saturation for my model immediately.

Re: redlantern

So - mash, introduce X quantity of water for sparge, bleed slowly, recirculate the rest, introduce clean water to replaced bled volume?
Remember, if your mash temp gets too high, you denature the enzymes. I believe your beta amylase begins to denature at 158°F, so you begin impacting the fermentable sugar quantity. If sparge is at 168°F, then you begin to shut down beta.

The idea would be to run a normal mash, perhaps just single infusion without any pump/wort heating; very standard. Then, at 60 minutes, start running the pump and heating up the wort to 168˚. Once that's hit, start adding 168˚ sparge water while bleeding wort very slowly to maintain 1" of water over the grain bed, or perhaps pumping in from below, as bonecitybrewco suggests.

My first question is - where is your efficiency lacking the most? What factors are keeping you where you are?

I would experiment with milling the grain better first.

In one gallon batches, a small hand cranked mill would be; fast, cheap, easy to control, and less involved. For engineering, try the cheaper, easier solutions first. In absence of success with that, move on to more elaborate ones.

My money is that a proper crush will give you a big jump in efficiency. It may also improve repeatability.

You make several good points - first of all, I will definitely start looking into buying and using a grain mill. Most I've seen are <=$100, which is totally doable, and I'd be improving every beer by using it, so yeah, I'll put that high on my gear wish list.

As for efficiency, I've been using a pitiful little hand-welded copper manifold for my last two beers, for which I got a crippling 50% mash efficiency, almost certainly due to serious channeling. The design is fairly textbook (by which I mean the slit spacing seems typical, and the center-of-tun to manifold to wall distance is on the money, but yeah, I probably should have just batch sparged so I wouldn't have had to worry about the design. In any case, I've just installed a proper false bottom, cut down to 7" radius, in my tun, and I bet good money I can beat 65% by running slowly through that. Pictures of both are below. So right there, I'll be improving my efficiency. Mash pH and temp are right where I want the, ~5.4 and 152&#730; for my current recipe respectively, so I'm not worried about that. Grain size is another factor, and as I can't mash out, having a heating element in the future that'll allow that will certainly help a little bit (so I've heard).

If you want to get really crazy - see if there are any food grade surfactants that do not negatively affect starch to sugar conversion.


http://garudaint.com/product.php?id=15


Seems that reducing water tension would help - but I have zero idea if that is possible for a successful beer.

A fascinating idea, and I will definitely be investigating this more. I'll at the very least read a few scholarly articles, and toss the idea past the aforementioned brew master. Thanks for the ideas!

Re: Bobby_M

The sprinkling effect of most sparge mechanisms is completely not necessary. The only good it does is not drill down into the mash but at the flow rate you'd be going for, a single drip is not a problem. You'll be leaving 1-2" of water on top of the grain anyway.

That's very comforting to know - hopefully my newly installed false bottom, coupled with a painfully slow sparge (probably 30 min for one gallon, like my last brew) will result in a healthy efficiency.

Finally, re: kombat

Indeed. I occasionally fly sparge, and I don't even have a sparge arm. I just lay a sheet of aluminum foil over top of the grain bed, and punch a bunch of small holes in it (with my thermometer probe). When it's time to fly sparge, I just run the return tubing from the pump back into the mash tun and lay it on the foil. The wort gets pumped back out, onto the aluminum foil, where it (presumably?) gently finds its way down through the small holes, trickling back into the grain bed.

I've seen that done, even on a one gallon system, and I've certainly considered it. I'll likely attempt the copper ring solution first, but should that be less than ideal, it's pie tins for me

Thanks everyone! And feel free to post any more reactions/ideas you have, all of it helps