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.

I've been listening to Brew Strong lately and again Jamil and friends have helped improve my brewing. In particular I listened to their yeast starter program and have just pitched the healthiest yeast starter for a lager ever.

The starter was for a Dortmunder lager which was batch #3 on the new HERMAN 7 powered by BrewTroller.

I've blogged about a number of things on the BT site about this brew, but some observations for my own reference:

• To chill to lager pitching temps, I need to use ground water initially and then do the last stage (maybe below 30C) with ice water.
• What I actually did to chill was use the plate chiller with ground water and pumping ice water through it to pre-chill the ground water. It chilled everything a lot quicker than normal, but most of my ice water was depleted too soon. I had to wait a while for the ice bank to restore to get to lager temps and had to pump ice water directly through the immersion chiller to do it.
• Use a hop sack in the boil kettle to minimise hop debris and therefore trub dumping into the fermenters.
• Improve the filter at the kettle pickup to fermenter.
• Wire in the fermenter fill solenoid and remove the kettle pickup solenoid.
• Put a meter on the mash level sensor to figure out what is going on between mash fill and mash empty and record notes.
• Get some air bleed valves so that the March pump primes reliably.
• add a low point drain on the system so it will clear all trapped water.
• Use the retrieved solenoid from kettle pickup to be the mash liquor in solenoid.

All up I was happy with how the brew day went. There is still a lot of debugging to do on the BrewTroller and hardware but it is a joy to use HERMAN 7 and is by far the best HERMAN yet.