Last time I outlined a number of changes that would improve the working of HERMAN 7. Changing the valve configuration and building an immersion chiller coupled with a busy work week meant that it was a push to be ready for brew day.

Despite this it was a pretty successful day, and definitely some huge steps forward. I forgot a spring while re-assembling one of the valves so I couldn't use the 'liquor in' line at all. It was inconvenient (especially after the work that went into it) but the workaround was simple enough. I'm glad that the system is modular and the camlock fittings work a treat.

The immersion chiller worked really well. It is nice to have proper control over the chilling process after battling for so long with an inadequately sized plate chiller. The immersion chiller takes away sanitisation anxiety, especially compared to the plate chiller. It also means that cleanup is much simpler because I don't need to rinse/PBW/hot water flush the chiller like I needed to before. The immersion chiller is aided by a whirlpool paddle on a motor that agitates the wort and whirlpools it.

The plate chiller has been re-plumbed as a pre-chiller. I didn't use it today but it is a simple matter to pump ice water through it to lower the ground water temperature. It seems to be a much better use of that piece of gear - no sanitation questions and still helping the chilling process.

I realised while brewing that I no longer had a need to recirculate liquor from the kettle drain via the chiller and back into the kettle. As the kettle is higher than my fermenters, I can gravity feed from the kettle once the wort is chilled. This eliminates the pump from the system and makes it far easier to sanitise. As an added bonus, it means one less solenoid valve is needed. This is handy because I needed an extra for the 'water in' modifications.

I don't yet like the way the BT is coded for running an electric kettle. I will speak to Matt about this on the BT forum but may end up doing some custom code to suit my system.

I still had one switching event that upset the controller during this brew. Last time I had at least half a dozen induced resets so again a significant improvement. The difference was having all three tuns run with shielded cable compared to only the HLT for the first brew.

Overall the brew went much better than last time. I started it later, had more time to do other things while brewing and had a lot of fun brewing with the BT. Next week it will be time to make another lager, and there are not too many things that need to be modified. The spring is already back in the solenoid and the only urgent thing is to hook up the ice water pump which is easy.

When I first joined the BrewTroller group the philosophy was 'let's build a stand-alone controller without the need for a computer attached'. It is a great philosophy, but it doesn't logically follow that you should never connect a computer to a stand-alone machine. Once the BT guys captured the vision for a PC app to enhance the BT, the coding for BTremote gathered momentum.

An early release of the program is available on Google code. Currently it shows information on a display panel that is more versatile than using the BT LCD. Information can also be streamed live to a web page for viewing on wap enabled phones and other mobile devices. I use my PDA to keep an eye on what the machine is doing while I am away from it. Soon the code will include graphing of data.

The development path will take us to remote control via ftp which is an exciting prospect. This may not be a great idea currently because the BT still has some fine-tuning before it will work automatically.

While these ideas bubble away in the background I've been thinking about a schematic layout view of the machine. A visual always provides better information than numbers in my opinion. Anyway I'd initially thought the simplest way to implement a schematic was to have different static images for each configuration for the machine in question. The BTremote app would then switch in whichever image is relevant.

One of the BT strengths is that it is very versatile, catering to vastly different machine layouts. For this reason each user is likely to need different images for each of their valve configurations. Asking people to draw these images with a wide array of 'paint' programs and incentive or ability seems problematic. Add to this that a number of switching configurations can be active at once and it becomes a nightmare to administer.

So I got to chatting with my friend Garrett who has done substantial work on his layout designer. As the BT crew renewed my enthusiasm for coding, my interest in Garrett's code has sparked his enthusiasm. There is still a long way to go, but I'm really excited about the potential of his work to enhance BTremote. You can see below a screen shot of my layout looking a lot prettier thanks to Garrett's rendering compared to my earlier schematic images.

So the open source brewing community seems to be humming along with lots of exciting developments in rapid time. As big Kev here in Australia used to say, "I'm excited!".

The solenoid valves from China are fabulous and show great potential for automated brewing. The problem is that they have a direction of flow arrow on them. Without really understanding why this might be, I had configured my valves to fill the hot liquor tun and mash tun with mains water against this directional arrow. The design choice was made because it saved me a valve.

After some testing it was quickly apparent that there were troubles with this approach. Without knowing why, whenever I turned on the solenoid that supplies mains water into the machine, the kettle solenoid, mash tun solenoid and hot liquor tun solenoid would all leak water in against the arrow flow.

At first I though I'd been supplied valves that were normally open rather than normally closed, as powering the valves slowed down the reverse flow (but didn't fully stop it).

I was determined to get to the bottom of this problem so I pulled a valve apart. It was a simple issue. The pressure against the arrow was providing the same mechanical action on the valve that the solenoid does - that is it opens the valve. If the valve was the oriented the other way around, the solenoid would have to work against the water pressure to open the valve. These things are designed to work against a significant back pressure, not a significant forward pressure.

It seemed a possible 'fix' would be to stiffen the spring that holds the diaphragm in position. I figured there must be some latitude here because the tuns won't hold a lot of pressure compared to the mains water. If that is so, the solenoid should have some spare power to act against a stiffer spring.

The simplest way to stiffen the spring was to lengthen its action. A nylon thread (4mm) fitted neatly. With the valve still apart, it was tested with power to see if the solenoid could pull against the stiffer spring.

So far so good.

So the next test was to reassemble the valve and try some back pressure against it. And even with a low pressure trickle on the outlet side of the valve the diaphragm still opened. The same test was done with stiffer springs until the solenoid would barely open under power and it still would not hold against the back pressure. These valves are simply not designed to be used this way.

In order to fix the water fill path, we will need an extra solenoid and need to move the path to the other side of the mash tun and hot liquor tun drain valves. A picture is better than a description here:

Above is the old fill path via the solenoid (circle) at right. The pressure against the three arrows at left create the problem. The proposed fix is below:

The single 'water in' solenoid is replaced with discreet solenoids for both mash tun and hot liquor tun, and now there is no back pressure from mains water against the existing solenoid valves.

I have an extra valve (and a spare) on order but it looks like they are 6-8 weeks away. In the meantime I intend to move the existing fill solenoid into the new HLT fill path and test the fix.

After a month or so of frantic building, the time came to run HERMAN through a brew session. There is an issue with the way I currently have the solenoids configured for filling the machine with water, so I did the fill the night before brewing. The level sensors are not yet giving reliable information so levels were eyeballed.

The process of pre-heat, dough-in and saccharification rest went like a dream. There was no trouble at all with valves getting clogged with grain matter. Also configuration changes are made so easy using solenoids and a controller. I am impressed with the BrewTroller and its versatility. More development is needed to truly automate a brew session, but there is a solid platform there already.

Filling the kettle with liquor went smoothly just like everything before it. It was great to see the copper liquid of a future English Bitter filling up the tun. And all was going so well during the heating of kettle to boil that I left the shed to do some other things.

And the next thing I knew the entire house lost power. OK, some troubleshooting. The residual current device (GFIC) on HERMAN had tripped and main house wiring RCD had also tripped. Normally the HERMAN one will trip early so the whole house doesn't trip. Also the breaker on the kettle line was tripped.

After another bit of testing it was apparent that the heater wiring underneath the kettle was at fault. Unfortunately this was sitting under 45kg of hot wort. The kettle was drained to the HLT and upon closer inspection I found that mechanical stress on a connector had caused it to fail - and a bolt nearby had caused the ground fault. This is what these breakers are designed to protect against, so nothing lost except the hour getting back up to boil.

The boil itself was pretty straightforward except that the BrewTroller wasn't able to figure out the wort was boiling. I've requested a temperature calibration feature to be added because my probe was reading 98.5C for boil. This meant I needed to time hop additions manually, but considering I haven't automated additions yet this didn't make any difference.

With the new build, I'd decided to chill liquor to pitching temperatures with a variation of Jamil's technique of recirculating kettle liquor while chilling via an immersion chiller. He uses return liquor to form a whirlpool. My differences are that I have a plate chiller and actually have a paddle built into the kettle to perform the whirlpool.

And here I came unstuck. The whirlpool was not effective because the liquor was drawn to the edge of the kettle and eliminated any effect of whirlpooling. The greater issue was that hop debris nicely caked over my pancake filter and prevented flow in the loop with the wort sitting at about 27 C. At first I thought the plate chiller was clogged but I could not drain the kettle into the fermenter. I had to back fill the kettle under water pressure prior to filling the fermenter. This was not ideal but I will make changes for next time.

So all up it was wonderful to brew with the new rig. It is so full of promise that I can't wait to brew again next. There are some major issues to sort out though.

• emf that causes the BrewTroller to lose the temperature probes
• filling via solenoid valves
• revisit (again) the chilling process

The last one seems most important so I will begin with that.

A few months ago I uttered something about actually finishing a brew rig before I updated to the next model. OK, so I could not help myself once the BrewTroller arrived. I never did finish working on HERMAN 6. I didn't finish coding for it. I never did design and etch a motherboard for it. And I never did get to a final plumbing layout.

But I did learn a lot along the way.

And all that experimenting has given birth to a new machine, and this time one that is radically better than all previous incarnations.

For a start, I'm not trying to do everything myself this time round. The BrewTroller is a good example of what I mean. Matt and Jeremiah have put a lot of work into a sanguino based brewing controller that is open source. The base model is full of features I'd barely even dreamed of, and I still get to code my own bits into it if I want to.

Also, having a like-minded brewing community means that ideas and resources are shared more easily. I have taken the plunge and bought cheap solenoid valves from China that so far look to be the goods.

And having solenoid valves available means extra features are easy to implement. I've added a mash idle configuration to the plumbing layout as an example of this. Until now when the mash reached temperature (or went too high), all HERMAN 6 could do was stop recirculating. Now the mash idle valve means that the heat exchanger can be bypassed, meaning that mash liquor is always recirculated, and that overshoots will drop to normal more quickly.

I didn't mean to kill HERMAN 6

Once I got the BrewTroller I did some experimenting to get to know its capabilities. Then to test it I needed to add pressure sensors, which I did. Then it made sense to wire the temperature sensors into the BrewTroller. And then I needed to test outputs so I built a relay board. And then I thought that it was time to buy zero-crossing solid state relays to power the hot liquor tun and kettle. And by then ... HERMAN 7 was so close to being a reality that it made no sense to hold onto nostalgia or legacy bits and pieces.

And behold ...

Before long the solenoids went in. And then it was a simple matter to wire in the relay board. And then the solid state relay board simply plugged in. And by then ...

... there was no more HERMAN 6 at all.

A quality upgrade

I've had the luxury this time round to do things right. This has meant buying quality components rather than cobble together bits and pieces that kind of work. I haven't gone to the degree of building everything in stainless steel (that remains beyond my skill level), but all the fittings are quality fittings, including stainless camlock fittings throughout the rig.

So close ...

There is still a small amount of wiring to do. I am short a few plumbing bits that I will need to get via mail order. I am short a few switches and LEDs to do a complete dry run. But by the weekend I will be ready for a wet run, and then the weekend after I expect HERMAN 7 will be making beer.