Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

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Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by skodaexploder » Tue Apr 27, 2021 9:45 pm

I have been using a 25L Klarstein Maischfest Mash Kettle Mash Tank since 2018, probably done a dozen of so brews. Then I had an overheating issue which was for some time worked around by manually holding the thermal cut-out reset button (on underside). Then finally this trick resulted in the thermal safety fuse blowing and tripped the electrics and could not be reset. The actual heating element(s) look damaged. I bought a new fuse, and new thermal cut-out switch, rewired the electrics but on first re-use the system tripped again within a few minutes and so I think it is the actual heating elements causing this which have been damaged in the overheating.

Does anyone have any experience of this, or have a suggestion to fix this please?

I will probably buy a replacement boiler/brew kettle. I think the problem with the 25L Klarstein is there is a build up of heat directly above the heating element under the grain filter and that there is so little movement of liquid at this point that heat is concentrated in this area, causes the tripping out issue. On draining the boiler then is always a large deposit of burnt on material that needs serious scouring. So a wider boiler with a more flexible grain bag (rather than a stainless steel filter cage) may be better. Hopefully folks on this forum can help with some suggestions.

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by guypettigrew » Wed Apr 28, 2021 8:38 am

Let me say first off--I don't have one of these, but I have just Googled it!

Does the heating element ned to be on during the mash? It looks as though there is some insulation built into the mash tank, so wouldn't it hold its temperature for the 60-90 minutes of the mash? If not, then wrapping some insulation round it would help.

Could you use the element in the mash tank to get the liquor to strike temperature (say 74°C), turn the element off, stir in the grain to get to your desired mash temperature then leave it until you want to separate the wort from the grain?

Guy

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by skodaexploder » Wed Apr 28, 2021 10:27 am

Hi Guy,

Thanks for your response.

The boiler was great initially but then start to cut out during the boil, so I physically pushed in the reset button on the bottom to keep the boiler on. And this became the norm for the next few batches. But then the boiler would cut out even in heating up the mash from room temp and ultimately the safety cutout switch melted into itself and the thermal fuse eventually blew!

So I changed all the components except for the element which looks odd and the coating has crumbled away. I started a heating cycle with water all was well for 20 seconds and then the system tripped the house fuse box. The new components seem fine and so I'm putting it down to the broken element which is permanently fixed in.

I can't see a replacement element anywhere and it seems solidly fixed to the base of the boiler.

I'm looking for a basic replacement, a friend uses a 40L Buffalo urn which does the job (if you remove the thermal cut out!). But rather than splash the cash now I wanted to explore the Klarstein repair via the forums.

Thanks again for your comments.

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by MashBag » Wed Apr 28, 2021 10:41 am

I have a good friend with one of these and he is really pleased.

The problem however is the element is bonded to the base. Replacement is therfore impossible... So its a new unit 😱
Last edited by MashBag on Thu Apr 29, 2021 6:32 am, edited 1 time in total.

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by skodaexploder » Wed Apr 28, 2021 11:08 am

Thanks Mashbag for your comments

The Klarstein was great until it started cutting out, although the design could be improved as sediment was building up and burning into the bottom of the boiler.

So yes a replacement is required, will the Buffalo boiler also die after a few years. I do about 6 brews a year so can't really justify an all singing and dancing unit

I'll check the forums for comments on new kit
Thanks again

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by guypettigrew » Wed Apr 28, 2021 11:41 am

A bit confused here! Where does the sediment come from if you're boiling wort? Surely the boil is vigorous enough to stop any sediment? You're not boiling with the grains still there, are you?

Guy

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by Eric » Wed Apr 28, 2021 11:42 am

Yes, it does seem that way. I have one, used it a week since on one elenent to boil down about 6 or 7 litres of low gravity runnings left from the previous day's brew for a starter, then forgot about them. The trip had operated when the volume was down to about 300ml of then highly concentrated and caramelised wort. After clearing the burned on remnants and pressing the reset it seemed to work fine.

The elements do get incredibly hot and to avoid overheating the inner base should at all times be clean, which is impossible if used as suggested. I frequently use another boiler and when not, the vessel is emptied and cleaned between the mash and boil.

The element is powered when the measured temperature falls by 4C, and hysteresis is such that the recorded temperature rises to 2 or 3 degrees higher than the desired setting. This makes it very difficult to mash at a fixed temperature without taking separate temperature readings of the grains and manually adjust.

I think you've been unlucky.
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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by guypettigrew » Wed Apr 28, 2021 11:51 am

Reminds me of Dave Line, this thread. In his first book he explained how he'd spent ages trying to design an electronic system to keep his mash at a steady temperature. I think he was an electronics engineer by trade. He found it really difficult because there was no way a heating element could ensure an even temperature throughout the mash without the highly likely probability of some of the grain burning on the element.

Which was when he realised simplicity was the key and he came up with the idea of the well insulated mash tun which needed no active heating during the mash. Home brewing using all grain and a mash took a huge step forward from then on!

Guy

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by skodaexploder » Wed Apr 28, 2021 1:32 pm

The burnt on crud may occur during the mashing and the boil. The Klarstein has a stainless steel filter for the mashing, then removed and washed through prior to the boil. After the boil and cooling, a lot of trub (?) is seen as the boiler is drained into the fermentation bin. Then once fully drained and emptied for cleaning you see the burnt on solids basically directly over the elements on the underside of the boiler.

As a replacement (basic) for the Klarstein, any suggestions?

Thanks

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by Eric » Wed Apr 28, 2021 2:28 pm

All single pot systems suffer from debris in the boil, but the Klarstein and some other vessels are affected more with small, high density elements directly heating the underside of the vessel, requiring only a small amount of material to cover the entire area above the elements.

Small particles get through the false bottom in the mash tun of my 3V system, but that wort is recycled until it runs clear. That cannot be achieved with the Klarstein. Instead, the wort is run into a spare vessel and the malt pipe is lifted and placed upon it. The Klarsein is then upended over the malt tube, then cleaned thoroughly before the collected is returned to it, except for the bottom inch or so containing grain fragments. Those are the poured back onto the mash and gently rinsed through before being added into the boil.

The finer the crush, the more the amount of debris that will find its way into the boil. The grain for the last brew was crushed using a 2 roller mill with a gap of 1mm which gave clearer runnings than with the previous smaller setting. Even so, many small particles made their way through the filter.
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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by MashBag » Thu Apr 29, 2021 6:47 am

Eric wrote:
Wed Apr 28, 2021 2:28 pm
All single pot systems suffer from debris in the boil, but the Klarstein and some other vessels are affected more with small, high density elements directly heating the underside of the vessel, requiring only a small amount of material to cover the entire area above the elements.
That's what I was going to say 😁

All of the more economically priced units bond the element to the base, cos its cheaper to make. But it also makes the unit disposable.

More expensive systems are build from components which are replaceable of they fail.

I do think you have been unlucky.
And I do think more expensive units are justifiable if you compare it to cost of the beer you make.
6x40=240 @ £1.99 = £477. 60

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by Cobnut » Thu Apr 29, 2021 11:01 am

I have friends with Klarsteins who have all noted issues with debris from the mash ending up burning onto the base and also with maintaining a steady mash temperature. I - in contrast - went for a Grainfather (quite a bit more costly to be fair), but it does have the advantage of wort re-circulation using the built in pump. I do get some scorching on the bottom of the unit, but in 50 or so brews I've never had it trip out.

As for the Klarstein, I know it has a tap near the base to drain the wort. So surely it would be possible to connect a small pump to the tap and recirculate to achieve similar results to the GF? I strongly suspect this would also help to achieve a more consistent mash temperature.

Has anyone done this?
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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by MashBag » Thu Apr 29, 2021 5:44 pm

Klarsteins do a version with a pump.

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by soupdragon » Thu Apr 29, 2021 7:52 pm

I've got one of the original machines of this type, an Ace.
When I started using it I suffered with burnt on crud covering the inner circle of the base, just above where the elements are. Lemon juice was the best thing to remove it but once I switched from Muntons Propino malt to Crisp the problem went away.
This is a machine with a recirculation pump by the way.

Cheers Tom

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Re: Klarstein 25L Maischfest Mash Kettle Overheating - Element Fault?

Post by skodaexploder » Fri Apr 30, 2021 9:20 pm

Thanks for all the comments. I'll look at a version with a pump.

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