Not a lot has been happening at least by way of construction on HERMLET of late. There have been way too many distractions which have included making beer to keep up with the increasing demand of an Australian summer, working out how to make the most of podcasts and lots of other things.

That is not to say that our inventive minds or making hands have been idle though. Some time has been put into the HERMAN machine which was left in a very raw state in it's most recent configuration while HERMLET took the focus. What we have done in recent weeks is use some of the new HERMLET technology to improve HERMAN. The prototype control panel has now been pressed into service on our brew rig and has already made it a lot more reliable and easier to use. If we can code and solder in the LCD before next brew day, it will also make the laptop an accessory rather than necessity.

The podcasts have been great as well. Now when I am cleaning the house, I am just as likely to be listening to the Jamil Show or something just as useful on my iPod. And it is through listening to Jamil that I've been doing a lot of thinking about chilling from kettle to fermenter.

The original HERMLET was conceived as a very simple/easy to use automated brewing system. It was inspired by (amongst other things) the brew in a bag movement (BIAB) and the no chill movement. Both methods are aimed at keeping things as simple as practicable for the homebrewer.

HERMLET has developed in complexity beyond BIAB but it retains its heritage in that idea. The issue regarding chilling has caused further thought through listening to Jamil.

HERMAN currently uses a plate chiller and while it is very efficient, it is not really possible to dial in a fermenting temperature in one easy step. Currently the chiller gets the wort down to the high 20s Celcius and a refrigerator works hard overnight if we need to drop it to lager temperatures.

When I first began all-grain brewing I used the cold water in the bath method of cooling wort. This is very slow and inefficient and is the likely reason an early beer I was very proud of was marked down significantly due to DMS. I soon upgraded to an immersion chiller and used this for a long time but was not satisfied with its inefficiency and in particular the amount of water it used. Water use is a very real issue in many parts of Australia. In Melbourne our water storage is currently at 42% and we are still in Spring. Many parts of the country have experienced prolonged drought. Water efficiency is a prime consideration at our place in a brewing system.

About 3 years ago we built a counter-flow wort chiller that served us very well. Its major drawback was its size. There are nagging concerns in my mind about both counter-flow and plate chillers because I can never be completely certain they are sanitary. An immersion chiller is boiled before use and the exposed surface is all that touches the wort. It can physically be cleaned of organic matter in a way that plates and inner pipes in a counter-flow cannot.

In talks about Helles and Pilsners, Jamil has raised that other fear for me - DMS. He argues that while a long boil (90 minutes) helps, another significant factor is chilling wort quickly. He argues that an immersion chiller acts on the whole wort and will rapidly cool it to an acceptable temperature regarding DMS production, while plate and counter-flow chillers only flash chill a fraction of the wort at any time. Much of the wort will stay too hot for too long using these last two chillers.

Jamil has developed a whirlpool system using an immersion chiller and a pump that recirculates wort back into the kettle. The whirlpool creates a far more efficient chilling system and has the added advantage of dumping hop debris and trub into the centre of the kettle.  By taking wort from the outside of the kettle when filling a fermenter, this matter is efficiently filtered out.

There is much to like about the idea, but there are a few issues to deal with before adopting it. Going back to the issue of water use, we intend to install a rain water tank that will not only be the source water for the chiller but will also take the "waste" water. This water will then be re-used on the garden, ensuring it is not wasted at all. The whirlpool idea also encourages a greater efficiency than my earlier immersion system.

The other issue I have with Jamil's idea is the method of whirlpooling. We have used a pump on the kettle outlet before and run boiling water through it meticulously as a method of sanitising. One day we did a double batch and both brews were rancid through a small amount of grain matter that was stuck in the pump housing. The housing is not something we want to take apart on a regular basis, so rather than use a pump for the whirlpool, we think a simple motor driven paddle that is incorporated into the immersion chiller is a better option. This would be sanitised as part of the boil in the same way as the chiller.

In the summer our city water supply temperature gets up to about 20 degrees Celsius, so to achieve lager temperatures we will experiment with iced water similar to Jamil's method for dropping those last degrees.

Now it is time to think about rain water tanks as we are experiencing some heavy thunder storm activity. It seems a shame to see all that water running down the drain ...