Will the autosparge be the choke point in my system?

[Smellyglove]

I currently have a HERMS where I route the flow back into the mash tun through a autosparge. I'm thinking of upgrading the herms-coil from the current 6mm ID to 10mm as 6mm obviously is a choke point with the small cross-section. I'm currently able to get a flow of almost three liters per minute, but I really want more. The rest of the tubing/barbs are no less than 11mm. (12mm ID hoses and 11mm ID barbs)

But. If I upgrade it, will the autosparge become my new choke point? As far as I remember the ID of the hose floating on top of the mash is also 6mm.

By upgrading the herms-coil to 10mm I've figured out the flow would multiply by 2.7 times. But I'm not sure if this number will be valid since the autosparge will still be there with its 6mm ID.

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[johngaltsmotor]

Yes. If you keep a 6mm part in an 11mm system it will be the limiting factor. It may also develop pressure. The pump will still try to work as hard but with less friction in the 11mm portions that energy will let it develop pressure where it reduces to 6mm.
That may not be an issue, but just something to consider. Or you put in a Tee with a vent line to allow some to bypass the autosparge.

 

[Smellyglove]

That sucks. So basically I can't use the autosparge for the herms loop and need to do some re routing and make another hole in the mash tun.

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[johngaltsmotor]

You can try it. One of 2 things will happen: it will flow more than it did before but now 2.7x more. Or (unlikely) the autosparge will fail in some other way. Being a simple brass valve I wouldn't expect this to be an issue.

 

[Smellyglove]

I just put it out for sale. Bad buy anyway. I'm using pumps all the way so I can just adjust flow with valves for sparging.

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[johngaltsmotor]

I would agree that with pumps an autosparge isn't as beneficial. They are better suited to gravity systems where you can't easily control the flow.
But tuning the exact inlet amount to match your drain rate won't be easy. A little one way or the other and 5 minutes of distraction and you've either got a dry bed or a flood.

 

[jCOSbrew]

There is a big difference restriction between 25' of 6mm tubing and 25' of 11mm tubing w/ one 6mm fitting. The pump capability is also a factor in max flow rate.

If you upgrade the coil you could easily measure the flow rate with and without the auto sparge.

 

[Smellyglove]

If you upgrade the coil you could easily measure the flow rate with and without the auto sparge.

I will do that first.


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[Smellyglove]

Am I correct in assuming since the narrower part of my system is at the end it will not matter as much?

Since it gets narrower the velocity of the wort will increase, so I will be able to maintain the flow.

If the narrower part is in the middle of the system, the velocity will increase through that narrow part but decrease when the wort exits it and continues through the wider part. slowed down by some sort of vacuum or something which will be after the narrow part.

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[JKoravos]

Am I correct in assuming since the narrower part of my system is at the end it will not matter as much?

First, no, that isn't correct.

Second, just upgrade the HERMS coil, it will make a difference. Having one 6mm fitting isn't going to kill your flow. It would be better if the whole system was 10mm, but a 10mm + 6mm fitting is still better than a 6mm coil + a 6mm fitting.

 

[Smellyglove]

Ok. Autosparge is not a choke point in my system

I upped to 10mm ID coil today and got 7L/min. Without any coil at all it was about 10L/min.

When I coiled the copper, I got a bit rough and made a flat spot in the coil, I got it mostly straightened out but is there any tips for making the copper round again?