Herms Recirculation Rate And Recirculation During Sparge

[Adam_Langman]

Hi all,

I assume most HERMS units use the March pump, rated at 21 L/min. From what I read most HERMS users talk about recirculation rates of 2-3 L/m.

1) Is 2-3 L/m recirculation rate about right?
2) If so, is this done by throttling the pump inlet or outlet?


Last, is there any benefit to continuing to recirculate while sparging? On the one hand I see the benefit of mixing the sparge water with the mash more completely, but on the other hand, does this make the process more of a batch sparge and lead to lower yield? I've attached a diagram of what I'm talking about:



I'd be keen to hear peoples thoughts.

Thanks,

Adam L

 

[Ross]

Adam,

Why would you want to recirculate the liqour you are trying to collect? Will just make your sparge much longer & if you are fly sparging you'd just be adding wort back to the rinsing water.

cheers Ross

 

[Adam_Langman]

Hi Ross,

Thanks for your comment, you may be right...

Here's my thinking. Keep the recirc flow at around 3 L/m but tap off about 1.5 L/m to the boiler. This way the sparge water would be at least partially recirculated and the idea is that by having longer contact with the mash that the sparge warter will collect more of the sugars.

Further, because the HERMS is still running, the temp can be maintained (at say 75c) to help prevent a stuck sparge.

I'm keen to hear your thoughts.

Thanks,

Adam

 

[AndrewQLD]

Adam, I think your over complicating it, in my mind a herms is best suited to batch sparging, unless you have a second pump to transfer liquor for the fly sparge you are creating too many variables as far as drain speed, sparge speed goes. It's not the easiest thing to balance your recirculation while avoiding compacted grain beds but from what I can see you will be increasing the difficulty quite a bit by introducing more liquid and recirculating while sparging, while at the same time trying to balance run off/transfer to the boiler.

Andrew

 

[Thirsty Boy]

you got it in your opening question - if you recirculate while sparging, you are more or less batch sparging and will most likely reduce your yield below what you could potentially get without recirculation.

You could - add your sparge water in batches and recirculate it in place of the step where a normal batch sparger would stir the mash - that would work. You could even no-sparge (or single run-off batch sparge if you prefer to think of it that way) by adding all your sparge water in one hit and re-circulating it, I've thought about sparging that way.

But if you are planning on sparging continuously anyway, re-circulating the wort back into the top will simply make it a less effective process.

TB

PS - and although it is far from a universal opinion, I think that your temperature probe needs to be on the outlet of your HERMS vessel, for me, as close as possible to the point where it re-enters the main wort as possible. So in your system, where your hose/pipe connects to your mash tun. If you are aware of the issues surrounding where you take your temperature measurements and you have made your decision, OK, I'm not arguing - but if it just seemed to you that it was obvious that your should be driving your control circuit from the mash tun temp... then there is more to it than that and it would be worth doing a little research on the topic.