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Some of you might find this interesting and if you have a way to whirlpool your wort (and have a need to do so), I’d love to hear what that is. Typically more info is always better than less when adding a new process to your brew day operations.
As with almost everything brewing related, one simply thing often leads to a chain reaction of adjustments. My preference for using only whole leaf hops came to an abrupt end when Hops Direct stopped importing whole leaf. Since 95% of my recipes are euro-styles, I am now resigned to using pellets, of which euro varieties are widely available. Of course my brewing system is designed for whole leaf, so one of the more pressing adjustments is how to keep trub from making it to the cellar. I think most brewers will tell you that you are better off transferring clear wort to your fermenter, though I understand there is an argument for having “some” trub in the wort as a fermentation aid”. In my ‘old’ way of brewing, the whole leaf hops clung to my kettle screen, creating a perfect filter for the trub. Now I have no screen at all (for fear of it becoming trub-clogged). For me, the way to resolve issues like this usually has me researching what breweries do to address the issue and it seems most use a whirlpool action to pile the trub (and spent hops, if those are free-floating as well) into the center of the kettle before drawing off clear wort nearer the sidewall.
My kettle is fairly large (31G) so for my more common 10G batches, the dimensions of the finished brew has the pool of wort being wider than it is tall. The standard 5 to 7gpm pumps were not creating much of a whirlpool action. Yes, there was a “whirlpool” but it was pretty lame. I jumped up to at Chugger Max TCP pump which runs at 17gpm. I noticed the inflow of wort was not enough to keep up with the pump (this due to most standard fittings being 1/2″ OD) coupled with other fittings along the way which are much narrower. After a fair amount of monkeying with it, I was able to change out enough of the fittings to get the whirlpool I want. I’ve included a link to a video I made of a recent test run here. Hopefully you can open this… https://drive.google.com/file/d/1JmBtNV0E5Zk7tB6D9PL1vTVTXwPny0Y6/view?usp=sharing
Funny to note that when I’m pumping hot fluids I’m still getting some cavitation in the pump head but when the liquid cools to about 170F the cavitation stops. So I may need to figure out how to address that issue next (change out from my counter-flow chiller to using an immersion chiller?).
Hmm….with a way to whirlpool in the kettle, I guess I can start making those super hoppy American style IPA’s now eh? (just kidding)
Jim:
I don’t have any advice on whirlpooling beyond what you are already doing. I have used a hop spider and/or hop bags to reduce the “gunky” hop material from ending up in my fermenter. The argument against is poorer hop utilization using these devices but the evidence is mostly anecdotal. Scott Janish in his new book about IPAs refutes that with some actual measurements at least during the boil.
The reason your pump is cavitating above 170 degrees F is because the pump suction is creating a vacuum at the pump inlet, which is reducing the partial pressure and causing the liquid to “boil” at a lower temp. The solution is to throttle the pump until the liquid cools a little.
The immersion chiller is probably interfere with your whirlpool. I am actually getting a Stout CounterFlow chiller because I am tired of wasting so much water with my immersion chiller.
You video looks like you have pretty good flow for the whirlpool.
Jim:
Thinking about it I did have one other thought. You could use a mechanical device to whirlpool instead of hydraulic (paddle on a drill).
Norcal Brew solutions sells numerous paddles for this purpose.
I have not used.
In my experience, “whirlpooling” has been more like “stirring”. It has led to a hazier wort because all it seems to do is efficiently stir and mix my wort causing resuspension of the trub. I haven’t dedicated too much effort to getting a true whirlpool, mostly because web forums where it’s discussed seem to demonstrate that it’s quite hard to achieve. Does your kettle have a trub dam on the pickup tube? I know we use similar SS Brewtech kettles, and mine came with a little silicone “dam”. It doesn’t block all the trub, but it does prevent a trub superhighway. I’ve gotten the clearest wort when I’ve left the kettle alone for some time, let the trub settle to the bottom, and had the trub dam do its job.
I do not have a trub dam but I do have an edge pickup tube. I am not too worried about trub (maybe I should be), with my cone-bottomed fermenter I let my beer clear up by dumping the trub and yeast cake after fermentation and before transfer to a keg.
Thanks for the feedback guys. Chuck – the cavitating information is helpful and it all makes sense that it’s the formation of a vacuum that’s causing the cavitation. I’m hoping to be able to allow the kettle to cool with the lid on just enough to get past that issue before beginning whirlpooling for about 15 or 20 minutes. I have no way to throttle the pump; it has a simple on/off switch. I saw the drill-powered paddle on YouTube but I decided to go with the pump/whirlpool approach. I’m fully invested in that now! LOL Aaron – I also saw the silicone dam approach from Ss and thought it looked like it might “slow” the uptake of trub to some degree. I have an extra large side-pickup tube arriving from Brewer Hardware on Friday, so by this weekend’s brewing I hope to have a something in place similar to Chuck, regarding exactly WHERE in the kettle the wort is drawn from. I’m inclined to agree with your “resuspension” concern and that issue will certainly be realized if I fail at creating the kind of trub collection I’m seeking. My hope is that the overall width of my kettle might will help to provide sufficient space for the trub to settle down in the middle of the kettle….but time will tell. I had a “sort of” whirlpool with last Saturdays Maibock brewing and I was encouraged by how well that rather anemic flow started to form a collecton of debris in the center of my kettle. As a result, the exiting wort was more clear than I expected. I did a tablet of Whirlfloc 5M before flame out, then let the kettle sit for a spell. Hopefully the improved flow will be the answer but the jury is still out on this project; experimentation continues.
Jim:
On the cavitation issue, another way to reduce the problem is to increase the vertical distance between the kettle and the pump suction – increase the Net positive suction head. I don’t know if you have the ability to do that.
Ok, like maybe moving the pump down to the floor Chuck?….instead of having it on the bracket just below the kettle spigot?
Throttling the pump flow is a good way to go IMO. A simple ball valve on the outflow side works very well. My understanding is that with magnetic impeller pumps, it doesn’t harm the motor because the impeller can still spin freely.
As you can see, I put valves on everything…
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OK, I can see what you and Chuck are essentially saying then is to slow the flow to avoid cavitation (hense Chuck’s suggestion to increase the head height to which the pump needs to lift the wort. But I think slowing the flow defeats my efforts to maximize the strength of the whirlpool….which was the whole reason for bumping up to the larger pump. Some of the so called whirlpools I’ve seen on YouTube with the smaller pumps don’t really look like they would pile trub anywhere, but instead would do exactly what you suggest and simply stir up the wort. I’ve gotten almost to where I want to be by limiting in-line restrictions (particularly on the inlet side, which is where Chugger warns is the biggest issue with the Chugger Max). Appreciate the feedback and suggestiobns though since I clearly still have work to do to get this situation dialed in properly.
BTW….I like your brewery cart! “a place for everything, and everything in it’s is place”, including the heat exchanger and pump. Is that a repurposed gas barbque?
Thanks Jim. I’m still dialing in the mise en place with regard to the cart and the cables running through the window, but yes, it is a repurposed BBQ. You can see the progression from A to B to C below:
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Yes, lowering the pump to the floor will increase the pressure on the suction and should not have an appreciable impact on flow rate. 3 foot of dynamic head is about 1.4 PSI which should make a difference. Try it and see if there is a difference.
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