Pump for Recirculation (Vorlauf)

I am thinking about buying a pump to recirculate my wort at the end of the mash. (I don't feel the need to recirculate during the mash at this point, but I may in the future.) Although I manually recirculate when I brew, I don't get the wort very clear, and I am convinced by @TheBeerery's blog post here that it's a good idea to get the wort as clear as possible coming out of the mash. While manual recirculation is enough to get rid of grain husks and a certain amount of cloudiness (proteins and lipids), I'm no longer satisfied with the clarity of the wort that it produces. That is my motivation to get a pump. I have a few questions and I would appreciate any other thoughts or advice people might have.

I'll be using the pump to recirculate wort through a 10-gallon cylindrical cooler mash tun. My plan is to arrange the pump in a position where I can prime it by opening the tap at the bottom of my mash tun and running the wort up through the pump head and then out into another silicone hose leading back into the top of the mash. I'll orient the pump head so that the inflow is at the bottom and the outflow is at the top, so that any bubbles should float up out of the pump. I'll have some kind of restriction on the outflow side to control the flow rate (maybe built into the pump, see below). I'll recirculate for a few minutes(?) (however long it takes to get clear wort), keeping the flow fairly slow so that I don't compact the grain bed. When the wort is running clear I'll turn off the pump, redirect the outflow hose into my kettle, and turn the pump back on.

So here are my questions:

1. I am leaning toward a Blichmann RipTide pump. It is only a little more expensive than a standard stainless-head March pump, and it has a built-in needle valve to control flow. People also say it is quiet, which is somewhat important to me as I live in an apartment building and don't want to annoy my neighbors. (The walls aren't that thin, though, and I won't be using the pump very often, so I could tolerate a moderate amount of noise.) I also like that it has an on/off switch. Early reviews noted a tendency for the impeller to stick, but the problem seems to have been addressed, and Blichmann is known for good customer service.

Any thoughts? Any experience, positive or negative, with the RipTide pump? In past threads, people have expressed positive and negative views of the needle valve, but I think it might be suitable for my needs since I want a slow flow rate. But please let me know if you have had bad experiences with it.

2. Would it be best to use a bazooka screen, a false bottom, a mash-in-a-bag system, or some combination of these? Or is it irrelevant? I was leaning toward a false bottom, but in John Palmer's How to Brew he suggests that a false bottom is not ideal for this purpose because its large surface area is slow to form a filtering layer of grain. Any thoughts are welcome. If it doesn't matter, I'll probably go with a bazooka screen underneath a false bottom.

3. How would you suggest affixing the silicone hose at the top of the mash tun (where it returns the wort)? I want to avoid splashing, so I plan to keep it below the surface of the wort, but I'm not sure how to accomplish that. Is channeling a concern? If not, it might be as easy as attaching some kind of heavy stainless steel to the end of the hose and putting it in the mash tun wherever.

Thanks to anyone who read this far and thanks for any thoughts or advice.

 

Thanks both of you, very helpful. I have not listened to the Master Brewers Podcast, but I will do so before making any purchases.

 

To summarize, it appears that the solids removed during recirculation contain fatty acids and zinc that are useful to yeast during fermentation. Including those solids in the fermenting wort results in less ester formation, less need for oxygenation, and a faster fermentation. (I am not sure that these effects would always be observed. The paper linked to in the thread @TheBeerery pointed me to does not appear to be publicly available. The interview with Magdalena Oehlschlaeger that @pweis909 pointed me to (link) seems to indicate that the "cloudy" wort was fermented at an unusually low temperature, which in my opinion could account for the lower ester formation that was observed. However, I can't really assess that conclusion without access to the paper.)

On the other side of the ledger, while zinc is desirable in the wort, fatty acids have mixed effects on the final product. In particular they have been blamed for staling the beer faster and for negative effects on head formation/retention. (You can read about that in the post I linked to earlier.)

It should be borne in mind that recirculation does not remove all of the solids from the wort. It merely reduces them.

Balancing these factors, I'm inclined to stick with my original plan of using a pump to recirculate the wort in an effort to remove a large portion of the solids present in the mash. I intend to use yeast nutrient during the boil to provide the zinc that the yeast require, and I intend to oxygenate the wort (as is my usual practice). I'll report back once I've had a chance to see the results.

In the meantime any other thoughts or advice is welcome.

 

Not sure if the problem is on my end, but I can't see the picture.

 

I agree that narcout's point on the AHA forum is compelling. I don't feel that my beer has a big shelf stability problem, but then again it's one of those things you might not notice until you taste the alternative. My beer definitely has foam issues, which makes me think a lot of lipids are making their way into the kettle. (In fairness, on the few occasions I've brewed hoppy beers, the foam has been better, so I suspect a lot of it is the type of beer I'm brewing. But it's not just sours, if I brew a porter that isn't very hoppy, the head retention will be poor.) So for my situation, trying a pump makes sense. But who knows, maybe my beer will get too estery and my yeast will suffer for lack of zinc, and I'll go right back to manually recirculating.

@SFACRKnight's experience is more troubling though. Have other people experienced those kinds of problems? I'm hopeful that because I'm only recirculating mash wort through it, it will be unlikely to get clogged.

 

Incidentally, this strikes me as an area where the Brülosophy approach could be highly misleading. (In point of fact Brülosophy has run two experiments, link one, link two, neither of which was well-designed to address the question.) What I mean is that the actual trade-off that brewers face is between (A) not recirculating, instead relying on the unsaturated fatty acids from the mash to boost yeast health in lieu of or in addition to nutrient augmentation and oxygenation, or (B) recirculating while relying on the addition of yeast nutrient and oxygen to facilitate a healthy fermentation. If you isolate only the recirculation variable, you must ensure that both worts have adequate zinc and oxygen. In Brülosophy's first experiment, no yeast nutrient was used, in which case the advantages of recirculation could be underestimated.

My personal view is that Brülosophy experiments should be "pre-registered" (that is, published ahead of time on the website), with a chance for interested homebrewers to comment on experiment design, and the results should be published whatever they might be. (In the real world pre-registration is used to address publication bias, the tendency to share only positive results, leading to a skewed perception of reality.) [Edited to add: pre-registration, when properly done, also addresses "p-hacking," the tendency to fish for a "statistically significant" effect even though it wasn't the original hypothesis being tested.]

But then again, this is easy for me to say, I don't run the website. For what it's worth, if I decide to run an experiment comparing pump recirculation to manual recirculation, I will post about it on this forum with ample opportunity for people to comment.