Homebrew: 2. Läutern

For the „Läutern“ (or „Abläutern“) step a „Läuterbottich“, a tub / bucket with a sieve inlay and outlet tap, is commonly used. The wort („Würze“) is transferred into the Läuterbottich and left for a defined resting time, the „Läuterruhe“. During this time the draff („Treber“) sets down onto the sieve and acts as an additional, finer natural sieve.

The wort is then cleared in two steps: 1. „Hauptguss“ (main pour) 2. „Nachgüsse“ (post pours).

  1. In the Hauptguss the first wort („Vorderwürze“) is progressively tapped off poured over the draff cake. This is repeated until the wort is clear and free of any trub, where the wort is ultimately transferred back into the brewing kettle.
  2. In the Nachguss additional water, matching the temperature of the wort, is progressively poured over the draff cake to extract the remainder of wort. The amount of water needed for the Nachguss is determined by the type of malt and target original extract of the wort („Stammwürze“). Once the draff is dry the newly won wort joins the brewing kettle.

In my first brew I wasn’t equipped with a Läuterbottich and had to rely on different containers for filtration. This has a huge downside: because the draff is exposed to air it quickly cools down – now, when the Nachguss is poured over the draff the water temperature could drop sharply, which in order would lead to a incomplete / uneven extraction.


Homebrew: 1. Maischen

The first step consists of extracting the wort out of the malt. This is done under controlled temperature setpoints and defined resting times.

To control the temperature I have bought an inexpensive PID controller + solid state array and hooked it up to a hotplate (bridging the internal knob).

Four temperatures are important to hold for a certain period of time for the conversion process:

  1. 47-53°C: „Eiweißrast“ – protein gets broken up by special enzymes. Today, this step is not always necessary since in processed malts very little protein is left to begin with. And a little amount of protein is needed for good foam on the final beer!
  2. 62-65°C: „Maltoserast“ – beta-amylase enzymes get re-activated at this temperature and begin converting starch to maltose (sugar). Later on, the yeast converts this sugar to ethanol.
  3. 70-73°C: „Verzuckerungsrast“ – alpha-amylase enzymes get re-activated at this temperature and being converting starch to dextrin. The yeast can only marginally process dextrin. Dextrin leads to a sweet and full-bodied taste in the final beer.
  4. 76-78°C: „Abmaischen“ – force remaining alpha-amylase to get re-activated to convert the remainder of the starch to dextrin. Having any starch left in the wort is highly undesired since this will lead to a fatty and unpleasant taste in the final beer.

A longer Maltoserast means more maltose and therefore ethanol gets produced, leading to a stronger beer. On the other hand, a shorter Maltoserast means more starch is left for dextrin production which leads to a fuller taste. In conclusion, temperature control and timing is crucial for achieving the correct balance between maltose and dextrin, which determine the final strength and taste of the beer.


Homebrew: An introduction to beer brewing

I got into beer brewing after receiving my first starter kit. Beer has a long tradition in Germany and hence the brewing process is very well understood both empirically and technically. In this post I’m going to give you a general introduction to the ingredients and process of brewing your own beer.

For brewing beer four ingredients are required:

  1. Malt: grains that have been germinated and temperature treated (germination produces enzymes which at the end get deactivated by hot temperature)
  2. Water: quality and mineral composition of the brewing water has impact on the taste (since beer consists mainly of water)
  3. Hops: plant belonging to the Cannabaceae family (the other member being Cannabis), brings the unique and bitter flavor to the beer
  4. Yeast: microorganism belonging to the Fungus kingdom, responsible for the fermentation process that converts carbohydrates / sugar to ethanol

And just like that, the brewing process can be divided into four main steps:

  1. „Maischen“: Add malt to water under a controlled temperature curve with defined resting times
  2. „Läutern“: Filter out residual malt particles, the so called draff („Treber“), from the raw yield and so called wort („Würze“)
  3. „Würzekochen“: Boil the wort and add the hop
  4. „Anstellen“: Add yeast to the wort to start the fermentation process

(Some intermediate and finish steps have been omitted, but will be explained later).