Sometimes I need to laugh at myself. I am big on ideas and small on action - too fertile an imagination with poor follow-through. Anyway, in a practical sense it means I'm reluctant to mark and drill a hole in a pristine piece of equipment - in case I change my mind.

I was reminded of this when I began to look closely at kettle modifications (to fix our spoilage bacteria problem). The old kettle outlet had been blocked up in an amateurish way, but the thing that made me smile was how I'd left the old heating element in the urn because I couldn't bear to remove it, just in case ... So it meant the kettle had two heating elements but only one in use, and two outlets but only one in use!

OK, so a few deep breaths, a socket set, and presto - one heater missing and two extra holes in the bottom of the kettle ... And then a few minutes with an angle grinder and the old drain point had been removed.

I had originally intended to use the central port for wort to fermenter. I tried to scrub up the fitting but it didn't look like it was ever going to be hygienic. I thought I might simply block up the old outlet properly by soldering in a plug. But it still seemed a patch on something that wasn't quite right. Ultimately the decision to cut it out was worth it.

The old heating element was mounted in two places in the base of the urn - so removing it left two new ports. I now had to figure out how to deal with three new holes in my aging kettle.

In the meantime, pulling apart bits on the kettle revealed a musty smelling barb fitting on the inner side of the polysulfone bulkhead. Have I mentioned I hate those things? Anyway it is now a primary suspect for our spoilage problems. A critical eye at this point is a good tool. No barbs, no small restrictive openings, and nothing that cannot be part of the clean in place loop. This means that a bulkhead fitting through to a three piece ball valve will all be smooth and capable of flushing with hot PBW. It also means that polysulfone disconnects will make way for camlock fittings. I wish I'd known where to find these things earlier. They are stainless, less restrictive, and cheaper to boot.

After some thinking, I figured the heating element holes could be used as a thermowell (temperature probe) and level sensor respectively. I already had bits  for the thermowell, and for the level sensor I put some fine stainless mesh on the up-side of the fitting with the idea that the sensor will plug the kettle from underneath. Because this is not yet installed, a simple copper plug was screwed into the port. The photo at above right shows the thermowell but also the kettle bottom after a clean in place. The PBW worked wonders on built-up scum. I will have to do a full-kettle clean, it is so effective.

The central drain port was fitted with a bulkhead fitting and plumbed into a three-piece ball valve that is screwed to the side wall of the kettle. With a camlock fitting on the other side, it has the feel of a professional piece of kit.

The clean in place process works well. It looks a little messy with all those hoses - but patching is quite simple. The old machine was much neater but less hygenic. I think I prefer this messy version. Now ... to make some more beer for Jess' birthday.

We brewed an IPA today and all went well, including hitting an efficiency of 79%, by far our best for a long time. The recirculating loop is doing its job well now.

While brewing though, the quaint idiosyncrasies of the control panel no longer seemed quaint, as several times we needed to power down HERMAN just to regain control. I realised that I'd been too focused on VB coding and not focused enough on fixing simpler things.

Anyway, with the machine cleaned up from the brew, I was determined to figure out what was going wrong.

The control panel itself was not at fault. As outputs were turned on, the supply rail varied by small amounts down, just enough to upset the analog to digital readings from the control panel. A double check with a battery pack produced the same effect as the PC power supply.

Unplugging the solid state relay interface cleared the fault, so I was getting closer. The interface box was actually the first part of the HERMAN 6 rebuild and was built over a year ago. I vaguely remembered having problems with it back then, and uncovered a circuit that was not quite right.

The original problem was subtle. The solid state relays have a drive voltage of 4-7 volts DC. The idea above is that a picaxe output directly drives the SSR to switch the AC load. The problem is that the LED (D1) needs a limiting resistor in place. I pulled off the cover of the interface and found resistors soldered onto the legs of the various LEDs.

Considering that the SSRs were ok to run from 4 volts, I decided to try some 150 ohm resistors on the drive line. I only had 180 ohms on hand, so they were plugged into the breadboard.

And presto, problem solved!

The supply voltage is now rock solid. The control panel now works no matter how many outputs are on. And I have lots of ideas about tweaks on the machine before we brew next ...

Some things to do:

• Add some hysteresis to the pump control while recirculating.
• Improve the receive communications on the VB program. At the moment it is missing every second send, and often getting out of sync.
• Improve the live graphing. Currently the brew is providing too much information and it is slowing down my tired old laptop too much.

We brewed again today, with a freshly plugged up false bottom and confidence that our recirculation loop would flow nicely.

We certainly improved the flow of things - and that was very satisfying. We made a Dortmunder and efficiency was up and the constant recirc gave us a beautiful clear nectar into the kettle. It has been a while since we've been able to say that!

But there was still something not quite right. The flow was still slow, almost too slow. It was at this point a few months ago that I began to chase my tail.

First thought back then was that it was probably the heat exchanger coil. There is a fair bit of extra copper in the recirc line and it must be sufficient back pressure on the pump to slow the flow.

Then it must have been a problem with the false bottom. And so imagining that there was air caught in the top of the pickup and getting sucked into the pump, I decided it needed a vent. I figured wrongly that the vent up through the mash tun would ensure that it would fix the problem. Umm, not so. The sucking of liquor out the bottom of the tun also sucked air in through the supposed vent.

So a complete circle - and the vent was plugged ... And today we were back at square one - the flow was less than adequate.

We were going to do a double brew today, but the first one took a long time due to the slow flow rate. So instead of attempting the second, we were determined to find the cause of the problem.

I had my suspicions, so I removed the false bottom from the pickup in the tun and checked the flow rate with an open hose through the bulkhead. And guess what? Just a dribble from the tun!

And here lies the unexpected side effect. Quite some time ago we thought it was a good idea to install polysulphone quick disconnects with bulkhead stops in the three tuns. I think at first they worked well. But over time we have had trouble with them, and in particular the mash tun one. We have gone through four of the male connectors - mostly because they get a bit tight and break apart on release. These connectors have a pin in the centre of the connector that pushes the stopper in the bulkhead open when the two are mated. In our system, the stopper is barely opening now, and restricting the flow from the tun severely.

The main reason I went for these connectors is for the convenience of the stop. It means you can pull the hose off without worrying about liquor leaking everywhere. Before this we had ball valves on the tuns, but they stick out and get easily knocked when cleaning them.

I've been thinking about a stainless replacement of these connectors for a while now. I've not found any with automatic stops on them, and maybe that is for good reason. Anyway, it is not hard to rig up a stop even if it means put a stop plug onto an open tun.

There are a couple of different stainless solutions I've come across so far.  My favourite Melbourne brewshop, Grain and Grape, has these connectors which are similar to the kind you get on domestic garden hoses, except in stainless and a little more robust.

But I like these from beerbelly which are the little brothers to the types used in serious breweries. 

And there are even 'stops' you can buy off the shelf.