I brewed a lager today that is a cross between a Helles and a Czech pils. It's a recipe that was inspired a long time ago by a lunar eclipse so I've given it the name Eclipse. The recipe tweak this time around is to use Summer Saaz hops which are a new breed coming out of my home state of Tasmania. They don't have the spiciness of Saaz and have a touch of the grapefruit flavours, but other than that they are similar to Saaz according to the description.

I haven't had any time to do improvements on the machine except that I'm running build #263 on the BrewTroller and Matt has coded in some of my asked for features. This time around the HLT temp is based on the Mash target plus a differential. Also the kettle power can be controlled on the fly now to get that perfect rolling boil.

Probably the most significant thing is that I had a moment of insight while looking at a graph of my last brewday. I've had troubles with mash temperatures oscillating nearly a full degree C. I've not been happy with that and the average temperature has been nearly half a degree low. While it is not devastating to brewing, it had puzzled me.

What I realised is that my dough-in mixer wets the grain well but it leaves hotter liquor at the top of the tun compared to lower down where the bulk of the grain is. With HERMAN 6, if I hit target the pump would simply turn off and it meant that this layering of temperatures stayed that way without me realising it. Now that HERMAN 7 has a heat bypass switch I have been recirculating for the entire mash and wondering why I was missing my target by a couple of degrees on the low side.

It also explains why I've needed to 'fudge' my strike liquor calculations. I've aimed a couple of degrees lower than the ProMash calculator for years, and to do that with the BrewTroller I've used a ridiculously high grain temperature.

So it turns out that my temperature probe sits at a high point in terms of mash liquor temperature. It also explains why my beers have tended to be on the dry side (which hasn't been an issue because that's my personal preference).

So with this as a theory, I've trusted the calculators today and what do you know ... the mash settled spot on the target of 66 degrees C. Getting this bit right and having the HLT track the mash target has meant that I've not only hit target, but the mash has stayed on target for the whole hour. I don't think it has ever been as finely tuned as today where my variation around target was +- 0.1 degree C. (Ignore the dodgy time scale - I've got some recoding to do there).

The wort chilling seemed to take a long time but it was okay because I'm not in a hurry while making beer. I chilled the kettle wort to 20C with ground water and then dropped to 8C via the ice bank water and pump. That all worked okay.

There are still lots of rough edges that need attention, but this was a very successful brew day. I've now got plenty of beer in the cellar which means that in the near future I can make those improvements I've been dreaming of.

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.

Today is a holiday in Melbourne because it is Cup Day. I don't care for horse-racing, and I don't even know who is running this year, but I do know the sun is shining and it is a perfect day to make beer and cook up a bbq.

I cooked my usb-serial adaptor on the weekend, and although yesterday was a normal trading day, I was down the coast with friends so wasn't able to access my normal places for a $15 replacement. I found a shop that had one and had to fork out $40 for it (ouch). I think the old one fried when I plugged the download cable into the picaxe. The picaxe was powered at the time and I had one of those moments of thinking 'this is not a good idea' ... but then it was too late.

The good thing about getting a replacement was I didn't have to quickly code the picaxe to show info on the LCD (which is finally working).

The brew day today has gone fabulously. HERMAN has pretty much worked without missing a beat, and the data log will give me some good info as well. The control panel is still not as reliable as I would have hoped for ... so I might try a zener diode on the supply line to see if that helps.

I did a pre-heat of mash liquor via the recirculation loop. I turned the machine on at 6am with cold liquor and it was ready by 7:30am. Not too bad for a cold start. I intend to code in a start delay on the picaxe. The dough-in temperature was spot on which was satisfying.

The mash essentially sat at 65C for nearly an hour without the recirculating loop running. Any overtemp causes the pump to turn off. The mash sat at 65.1 for about 45 minutes. When the pump fired up, there was sufficient 'cold' liquor in the loop to drop the mash temp to 62.5 before restoring it again quite quickly. I think that an additional bit of logic that runs the pump for 30 seconds if it has been off for 5 minutes might help. Something to test anyway.

Speaking of the pump, I need to fix a bug in code. At the moment the pump can be turned off on the control panel and still run if a mash target has been set.

I was interested to see how effective the kettle's auto power settings would be at preventing a boil-over. It certainly helped, but 5 minutes into the boil the system surged and would have boiled over without intervention. If this is to be a fully automated machine, it looks like additional sensing (possibly ultrasonic) will be needed. A brief pause in kettle power was all that was needed to 'break' the protein layer that causes boilover.

Another note regarding kettle functioning is that I need to tweak the duty power code to improve the way it operates. Currently a 50% power duty has the kettle off for 10 seconds and on for 10 seconds. I am sure this increases the likelihood of boilover, and it is not all that elegant a way of controlling power. If the picaxe is run at 16 MHz instead of 4 and the interrupt timing sequence is recoded, I am sure that it will help.

I am brewing a double-batch today, so the cooling liquor was directed into the hot liquor tun and mash tun, ready for the next batch. The water collected was slightly less than needed but very close to ballpark. The advantage of being able to do this is that the liquor comes out of the plate chiller at around 54 degrees C, so most of the heating has already been done.

Brew one was an American Cream Ale. Brew two will be an American Wheat. Each batch will be around 45 litres. We have actually run out of beer and these ought to ferment quickly and be nice 'lawnmower' beers suitable to the warming weather here.

We figured it was time to brew beer again. The plan was to create two side-by-side batches of our favourite North German Pilsner. One batch would be made as normal using only Tettnang hops; the other batch would be identical except it would be hopped exclusively with Spalt.

The inspiration for this move came from a recent trip back home to Tasmania where we sampled Moo Brew Pilsner. It is a German Pilsner and they use Spalt for their hopping. We'd not used it before, but Ross at Craftbrewer stocks it.

A double brew takes most of the day when things go smoothly. If you have been following recent blog postings you may remember we have has some issues of late with flow in the HERMAN recirculating loop. I cursed being distracted last time while brewing that I had not done the testing needed to figure out where the problem was ...

All seemed to be ok at the start. The change to pre-heating the mash liquor in the tun by using the recirculating loop was promising. Not only does this mean we can hit our mash targets spot on, it means we get to test the loop before adding grains in the tun.

Dough-in worked out fine, and the mash hit its target of 63 C as hoped. All good so far. But while liquor flow had been fine pre dough-in, the small trickle once the grains were added meant for a painfully slow brew day. At least the temperature was right. Now we needed to figure out what the problem really was ...

We disconnected the hose at the mash tun outlet to allow the liquor to drain out without assistance. It was surprising to see that flow was even slower than with the pump in the loop. This meant that the pump was actually improving flow by adding suction to the false bottom connection (not a desirable thing). This proved that something was seriously amiss somewhere.

So the next bit was to check the quick disconnect right at the tun itself. The disconnect is designed to close when the plug is pulled out, and the orifice itself is quite small. Using pliers to press the bulkhead stopper in (and open it) produced the same result .

There was no option but to transfer the contents of the mash tun into another vessel and carefully check what was happening with the false bottom and pickup tube. So with some water as back pressure and the false bottom exposed, the problem was glaring right at us ...

Firstly, the water back-pressure blew air and grains back up out of the works. The plug that had been put back in place to stop the 'air vent' was no longer there. This meant that grains were able to get sucked into the take-off tube and block it up. No amount of liquor pressure through the false bottom would free up the works - it would always re-block itself with more grain.

What is so frustrating is that we had thought we'd fixed this problem. Obviously the fix was not robust enough. We temporarily fitted in another rubber plug, but I think a soldered cap will be needed.

Anyway, with the grain back in the mash tun, all was tested and finally the flow around the loop was normal.

We'd lost so much time by now that we did not wait for the grains to heat to mash out. Our efficiency suffered because of it, but at least we knew we could run the second batch through with confidence.

The second batch of Pilsner mashed beautifully. We made 85 litres of beer yesterday and I've been reminded again that simple fixes often create more trouble. When figuring out solutions, industrial strength lenses are needed so that things are fixed once and for all.

I decided that I'd had enough of mis-hitting dough-in temperatures due to the large thermal mass of the mash tun. The result seems to depend a lot on the ambient temperature, and I don't brew often enough to take into account a 40C day compared to 19C today, or 15C tomorrow.

So I set ProMash's thermal mass to 0 because I intended to pre-heat the tun. I was after a protein rest of 54C, and ProMash suggested 59C for dough-in.

I might have been more patient (maybe this is the problem ), but I doughed-in with the mash tun and liquor at 61C. It was pleasing to see that the result was a protein rest at 56C. A little high, but I'm not so worried today as I'm anxious about the step to 64C.

The mixing paddle was left to stir the mash with no liquor recirculating as the hot liquor tun was heated to 80C. I figured if this was too much heat, I could turn the pump off anyway. The liquor to grist ratio was around 2 litres per kg grain, which meant that there was sufficient room to top up the mash tun with hot liquor to help the step as well.

Some top up liquor was added to the mash tun and then I attempted to recirculate. I'll save the details for another post, but I struggled to get any meaningful flow in the recirculating loop. Damn - over to plan B, a pseudo decoction.

Eventually I managed to get things flowing again, but it meant that much of the performance testing of the machine was out the window. I decided on a long rest at 64C to recover from the stress of the day so far, and to give me a chance to get down to the local fresh fruit market to pick up some yummy citrus for the Belgian Wit.

The saccharification rest had lingered a little low at the early part of the crisis, so I set the HLT to 68 degrees after a while to allow the mash to slowly ramp up to 65C. After settling down, it was rock solid at 65.1. It is pleasing to see it working so well, although it is obviously very dependant on recirculation flow.

With about 15 mins to go, I let the mash sit without recirculating and heated the HLT to 85C - again testing the theory that doing this will speed up the step change, and that the HLT might settle at around 78-80 by the time the mash has reached mashout (around 75-76C).

I didn't actually time it, but it seemed to take a long time to ramp up from 64C to 75. It would have been great in hindsight to have the laptop acting as a data recorder so I could simply graph what was happening. There were too many hiccups and distractions today, so it would be good to have a simpler brew day and do just that.

One of the complications was caused by old malt coming out of the heat exchanger coil. I managed to fill the plate chiller up with the stuff and had a rotten time trying to clean it. I just hope that the brew is clean enough to not suffer contamination from here.

It seems the heat exchanger will be slower for step mashing, but there are some workarounds that look good - like pre-heating the HLT while the mash sits. With a good recirc flow, it looks like the heat exchange coil could be made more efficient - either that or slow the liquor flow down - I'll need to think about that.

Anyway, the Wit is now pitched and fermenting - this means that with the batch we did 11 days ago we should have about 80 litres to get us through the Autumn. I think a Kolsch might be on the cards next.