Anti-boil for HERMS?

[Mardoo]

I'd strongly avoid going for an oil or glycol arrangement, as while you'll get a higher temperature gradient, there will be more boundary layer effects. I don't think the risk of having a mini deep fryer running is justified. Boiling dry is an easy problem to fix.

Can you explain to this particular idiot what a boundary layer effect is? It's OK to talk a little loud and use big gestures. Might help me get it

And a mini deep fryer would make lunch a doddle…

 

[Adr_0]

Can you explain to this particular idiot what a boundary layer effect is? It's OK to talk a little loud and use big gestures. Might help me get it

And a mini deep fryer would make lunch a doddle…

Probably that with the higher temperature difference means that the temperature on the very inside surface of the coil - being wort - is actually quite a bit higher than the bulk/average temperature, which the probe/controller will measure.

This should only be for a couple of minutes - as the wort will still hit the temperature setpoint and the element will switch off - but if done enough may denature some of the enzymes moreso than at higher wort flow rates or with larger HEX vessel.

A larger HEX vessel also means more lag, which will cause overshoot... So it's a bit of a balance.

 

[MartinOC]

Gent's, KISS.

Use water in your HEX vessel with a small vent to prevent pressure build-up.

You can always top-up the HEX before starting the next brew (via the vent) & it's only water...

 

[klangers]

Can you explain to this particular idiot what a boundary layer effect is? It's OK to talk a little loud and use big gestures. Might help me get it

And a mini deep fryer would make lunch a doddle…

That the oil might get hotter than water, but since it's more viscous and doesn't boil at the same temperatures, there won't be as much convection as when it is water. That means that close to the outer surface of the coil, the oil is much cooler and stays there because of lack of convection.

This means that while you've achieved a higher overall temperature difference, the heat transfer rate (the watts) is actually lower. I can't say this is a certainty, but it's a definite possibility.

 

[Mardoo]

Thanks!

 

[checkers]

I am building the exact same system at the moment!!! 50L Malt pipe in 70L BK

I am drilling my malt pipe out with 3mm drill bits [emoji23][emoji23]

I was looking at buying the same herms coil of nev but am tossing up if I can't sort something out a little cheaper..

Nev would be able to answer your question about boiling solution or how to avoid it.

 

[Gibbo411]

I am building the exact same system at the moment!!! 50L Malt pipe in 70L BK

I am drilling my malt pipe out with 3mm drill bits [emoji23][emoji23]View attachment 107108

I was looking at buying the same herms coil of nev but am tossing up if I can't sort something out a little cheaper..

Nev would be able to answer your question about boiling solution or how to avoid it.

I know the struggle, though I found cutting slits helped a lot.

 

[Adr_0]

I am building the exact same system at the moment!!! 50L Malt pipe in 70L BK

I am drilling my malt pipe out with 3mm drill bits [emoji23][emoji23]View attachment 107108

I was looking at buying the same herms coil of nev but am tossing up if I can't sort something out a little cheaper..

Nev would be able to answer your question about boiling solution or how to avoid it.

Bloody hell...

 

[MHB]

Not an original idea, goes back to Graham Wheelers first book (so early 80's) glue a sheet of graph paper onto the surface you are drilling.
If you texter out the zones you want to perforate with a good black texter and glue the sheet down with something like Aquadhear or some other PVA or water soluble gum, then it just becomes a case of drilling every third box or so. Helps help to keep it all neat and lined up and you should be able to see where you have marked out through the paper

On the drills, if you ask for Jobber Drills, they have a point on both ends, mainly made for pop riveting, they are pretty cheap and come in packets of 10-12, don't be afraid to throw them away SS kills drills - a small pot of a drilling lubricant is also a good investment.
Mark

 

[TheWiggman]

Regarding the query behind using a different fluid, I challenge the logic. If you're concerned about boiling the HERMS water you're only looking at a single scenario - no flow (be it a blockage, airlock or accidentally closed valve). What will change in this scenario if you use oil or glycol? Nothing, there will still be no flow. The only difference will be that instead of boiling water you'll eventually boil glycol or oil, the only saving grace being you will have more time until it boils so you might catch it before it does so.
My recommendation: keep using water. I'd much rather boil water than oil, because if you're boiling oil you'll lose a lot more than an element.

 

[checkers]

I know the struggle, though I found cutting slits helped a lot.

I cut slits in my 19L big w malt pipe in my keggle.. with wheat in the mash and a big bill I struggle with recirc and overflow.. I'm hoping this will give me decent flow in the new system.. few more beers to be had while on the drill ;-)

 

[checkers]

Not an original idea, goes back to Graham Wheelers first book (so early 80's) glue a sheet of graph paper onto the surface you are drilling.
If you texter out the zones you want to perforate with a good black texter and glue the sheet down with something like Aquadhear or some other PVA or water soluble gum, then it just becomes a case of drilling every third box or so. Helps help to keep it all neat and lined up and you should be able to see where you have marked out through the paper

On the drills, if you ask for Jobber Drills, they have a point on both ends, mainly made for pop riveting, they are pretty cheap and come in packets of 10-12, don't be afraid to throw them away SS kills drills - a small pot of a drilling lubricant is also a good investment.
Mark

Cheers bud, I work in construction and have an endless supply of bits.. I've been using lanolin spray as cutting compound.. can only assume its less toxic than trefolex.. when I'm done I'll hit it with a flapper wheel and isopropyl alcohol to get all the shit off.. then I just need to sort herms cool and I'm off and brewing on the new rig!!

 

[Kingy]

I used oil in my home made herms a few years ago and done a few tests, can't remember much about it but the ramp time was way better with the oil. However it can get messy and it stinks after a few brews. It would be a bitch to do an oil change on it.
A few people commented that I could cook some chips while brewing. I remember I checked the temp of the oil and it was pretty high.
Definately not worth the hassle.
If you use glycol make sure you get food grade glycol.
I have one of Nevs herms now (for a while actually) and I've lost 1 element from it boiling when I turned the pump off and left the heat on and left the shed to clean some gear.
I usually don't drink until the boil is started and the mash tun is cleaned these days . And I check the level in the herms at the start of every brew.
I won't be losing another element that's for sure.

 

[Stubbie]

Thoroughly agree poor or nil flow rate is the root cause and a flow rate sensor of sorts would be ideal. An alternative is to monitor HEX water temperature and limit to, say, 98C via a controller, preferably with an SSR output. Use to break input signal to the HEX element SSR. Can have the controller sound an alarm when the set (near boiling) temperature is reached.

My HEX is powered by a 3.6kW element in under 3L of water and with a stuck sparge a HEX boil can be only a matter of seconds away. So I've been thinking of including the aforementioned.