Kettle parameters

Temperature control

Max power

Defines the maximum heating output for this kettle (default: 100%).

Use lower values for small kettle volumes (for example 20 l) to avoid aggressive heating and boil-over. In practice, reduce Max power and Power from transition together.

At the end of this chapter you will find two examples for calculating required power.

Temperature delta to target

Defines how close actual temperature must be to target before the rest timer starts (default: 0.3°C).

Example: target is 63.0°C, current temperature is 62.7°C. With delta 0.3°C, the timer starts already at 62.7°C.

This helps avoid unnecessary extension of rest time in slow final approach phases.

Transition to cooking [°C]

Defines the temperature where Brautomat recognizes the transition into boil mode (default: 95°C).

This is not the physical boiling point. It is the threshold where PID can hand over to fixed-power boil control.

Power from transition [%]

Defines fixed output power after the transition threshold (default: 100%).

For large volumes (about 35 l and above), 100% is often fine. For smaller kettles, reduce this value (for example to 75%) to reduce boil-over risk.

From version 1.60, this can also be set directly in mash plan command steps:

• IDSTHRESOUT:80

• MAISCHETHRESOUT:80

Disable PID for cooking [on/off]

Defines PID behavior above boil target temperature.

Typical example: boil target in mash plan is 98°C.

If enabled (default), PID stays disabled above target and boil runs with Power from transition. This supports a stable rolling boil.

If disabled, PID is active again above target and can reduce output strongly (even to 0%), which may stop boil if overshoot occurs.

Sensor error power [0-100%]

Defines fallback power if sensor errors occur.

• 100%: continue operation ignoring sensor error

• 0%: pause mash process and switch heating off

Brautomat starts sensor-error handling after 3 consecutive invalid sensor readings (about 6 seconds at 2 s scan interval).

If the sensor recovers, Brautomat continues automatically.

Note: Max power still limits effective output. Example: Max power 75% and sensor error power 100% still results in max 75%.

PID Manager

Interval (SampleTime)

Defines how often required power is recalculated (default: 3000 ms, range: 1000 to 7000 ms).

Smaller intervals react faster but increase controller activity.

PID algorithm

Available modes:

• Manual PID mode: use custom Kp, Ki, Kd

• IDS PID mode: calculate PID from AutoTune Ku/Pu for GGM IDS systems

• Relay PID mode: calculate PID from AutoTune Ku/Pu for relay-driven systems

AutoTune

AutoTune noise band

Used for extreme-value detection (min/max). It defines the minimum change required to detect a new extremum.

Typical defaults:

• GGM IDS: 0.2

• relay/SSR NACHGUSS kettle: 0.5

Value range: 0.1 to 1.0.

AutoTune data series (lookback)

Defines how many measured values are used for extreme detection (default: 50, max: 100).

Highly insulated kettles may benefit from a larger lookback during cooling phases.

AutoTune debug

Enables detailed AutoTune logs for diagnostics.

If enabled, logs are also available during brewing.

These parameters are setup-specific. You can tune them with a water-only test run before brew day.

Profiles

Brautomat can store hardware profiles for different kettle setups (for example small and large batch kettles).

A profile includes all kettle-related parameters. Profiles are saved in the /Profiles folder.

• Save creates/updates a profile file

• Delete removes the profile file from flash

At startup, Brautomat loads the last selected profile.

Calculation of required power

This section is optional background information.

For mash ramping, a target of about 1°C per minute is common.

Simplified estimate:

required power P = m[kg] * 75

Where m is mash mass (grain bill + strike water).

Assumed IDS max power:

Pmax = 3500 W

Power percentage:

required / available

Example 1

Grain bill 9 kg, strike water 35 l:

m = 9 + 35 = 44

P = 44 * 75 = 3300

Needed: approx. 3300 W for about 1°C/min. With 3500 W available:

3300 / 3500 = 0.94 = 94%

So IDS target power is about 94-95% (IDS:94).

Example 2

Grain bill 5.9 kg, strike water 26.5 l:

m = 5.9 + 26.5 = 32.4

P = 32.4 * 75 = 2430
2430 / 3500 = 0.69

So IDS target power is about 69-70% (IDS:70).

Why mass * 75?

Base formula:

P = m[kg] * c * T / (t * w)

Variables:

• m: mash mass (strike water + grain bill)

• c: specific heat capacity of mash (approx. 3600 J/(kg*°C))

• T: temperature increase (1°C)

• t: time (60 s)

• w: heater efficiency (0.8 assumed)

c * T / (t * w) = 3600 * 1 / (60 * 0.8) = 75

Hence the simplified factor 75.

Specific heat capacity note

The simplified 3600 value has a small tolerance (about 2%, depending on extract and temperature).

Reference values:

• malt grist: about 1570 J/(kg*°C)

• water (50-80°C): about 4190 J/(kg*°C)

See also Brewing Magazine.