Brewing with RAPT Gen 4 BrewZilla
Brewing | RAPT Gen 4 BrewZilla
Mashing
Once you have assembled your boiler, digital controller and malt pipe you are then ready to add grains to begin mashing.
Ensure that you have added the correct volume of strike water and this water is heated up to the correct strike temperature according to your recipe. Generally, the strike temperature is a few degrees Celsius above your desired mash temperature.
Then add your malt pipe with the bottom perforated screen installed into your boiler, such that the top lip of the malt pipe rests on the wire supports which are nested in the groove at the top of the boiler.
You can then pour your grain into the malt pipe.
It is best to stir the grain periodically while pouring it into your malt pipe to break up any dough balls (dry spots). Once you have added all the grain thoroughly stir the grain to ensure all the dough balls have been broken up. This will take about 2-5 minutes.
Then insert the top screen into the malt pipe so that it lightly rests on top of the grain. After all the grain has been stirred in and the top screen inserted, you can then assemble the recirculation arm to recirculate the wort during the mash.
You may find that the temperature may overshoot the target temperature if the heating power is set to 100%. To maintain a more stable mash temperature, reduce the heating power to between 30-40%. However, the exact power setting is dependent on a number of variables such as your grain bill, whether your unit is jacketed and heat loss from the system for example so the exact required power can vary.
Mash Temperature Reading
The temperature on the digital controller reads the temperature at the bottom of the boiler near where the elements are mounted. It is important to understand that this is not the core temperature of the mash. If you recirculate long enough the mash temperature will eventually be close the measured temperature displayed on the digital controller.
With that said if you want to increase the temperature of the mash it is normally fastest and easiest to overshoot the desired mash temperature by a few degrees while using a secondary calibrated thermometer in the mash to keep an eye on the core temperature of the mash.
If you are finding that you are overshooting your target temperature during the mash for example, then adjust your heating power.
The probe placement has been designed to prevent the element from overheating and scorching the wort by taking the temperature of the wort closest to the elements. This is why your strike temperature needs to be accurate!
Adding a Heat Exchange Dish (HED) to the False Bottom of the BrewZilla can help get better flow over the base of the boiler and thus the temperature probe. This can increase accuracy of temeprature readings during brewing.
The BrewZilla includes Ultra Low Watt Density Elements (ULWD) meaning brighter beer can be brewed with the fear of scorching and burnt off flavours.
For the best possible accuracy and control of the mash process and temperature, the use of a RAPT Bluetooth Probe is recommended. This allows the temperature to be measured directly from the mash. This decouples temperature control from the elements so you cn quite easily acheive more precise and faster temeprature adjustments.
For a detailed guide to using the RAPT Bluetooth Probe with the RAPT Gen 4 BrewZIlla refer to the Bluetooth Operation section.
Pro Tip: If using the RAPT Bluetooth Probe for the mash then set the Sensor DIfferntential to a low value to minimise temperature swings (~2°C). You can increase the Sensor Differential if doing a step mash or a mash out (8-10°C)
Sparging
Once you have mashed your grain for 30-90 minutes (typically mash time is 60 minutes) it’s then time to sparge the grain. Sparging involves rinsing the grain bed with warm water to extract as much sugar as possible without extracting undesirable tannins.
Using the malt pipe handle lift the malt pipe out of the boiler and rotate 90 degrees until you see the feet of the malt pipe located near the halo ring (wire supports). See picture below.
The Gen 4 BrewZilla includes a two-stage malt pipe. This gives you the option to lift the malt pipe half way up and support it on the halo ring. This makes it more ergonomic, making it easier to lift the heavy malt pipe out of the liquid. If you are making smaller batches only raising the malt pipe up halfway may be preferable.
It is advised to have the top screen inserted into the malt pipe during sparge to prevent channelling through the grain bed which can reduce your efficiency.
Once the malt pipe is suspended above the boiler and is securely supported by the halo ring then pour warm water (approximately 75-80°C) onto the top screen inside the malt pipe to rinse the grain of the majority of the remaining sugars. Using brewing software such as BrewFather or the RAPT Brewing software is the best way to calculate required water quantities.
A secondary vessel or HLT (Hot Liquor Tank) is receommended for this process. A 35L Digiboil is ideal for this.
Pro Tip: You can turn the heat to boiling temperature and change the heat power to 100% as soon as the malt pipe has been lifted. This will bring the wort to a boil faster.
Boiling
Boiling is one of the final steps of making beer in the BrewZilla. Simply set the heating power to 100% and set the target temperature to over 100°C which will result in the elements remaining on continuously. If you set the controller to 100°C you may find that the elements turn off for a brief period once this temperature is hit. Ideally you want the elements to run at full power during the entirety of the boil.
Once you have reached a boil make your hop additions and boil as long as required as per your recipe. A normal boil length is 60 minutes however this can vary between beer styles.
Pro Tip: If you are running a Profile for the brew, you can set alerts when creating the profile as a reminder of when to add hops (for example).
Boil Temperature Reading
At sea level water will boil at 100°C. If a temperature of above 100°C is displayed on the controller while the wort is boiling then you will need to calibrate your temperature probe
If a temperature below 100°C is displayed on the controller while the wort is boiling and you are at sea level then you will need to calibrate your temperature probe.
Water boils at a temperature less than 100°C at altitudes above sea level. So, if your wort is boiling below 100°C and you are at a high altitude then correlate the displayed temperature with the boiling point of water at your elevation to determine if calibration is required.
Cooling
The BrewZilla includes an immersion cooling coil*. An optional counter flow can be purchased separately but these are complicated to use and it is sold as an optional extra.
*35L and 65L models only. Immersion chilling is not receommended for the 100L BrewZilla - a counterflow chiller is much better suited.
The immersion chiller is easy to use and clean, simply connect your garden hose to each end and run cold water through the chiller while it’s immersed in the wort inside the boiler. Place the immersion chiler into the boiling wort at least 10 minutes before the boil ends in order to ensure it is sanitised.
If you were looking to save water you can also connect the immersion chiller to your pump on your BrewZilla and then immerse your immersion chiller in a bucket of ice water.
There are a number of optional fittings which can be used to easily connect your garden hose or pump to your immersion chiller which can be purchased separately.
Connecting the immersion chiller to a garden hose (recommended)
The easiest way to connect a garden hose to the immersion chiller is to simply push the garden hose over the immersion chiller and secure with a hose clamp.
For a more ergonomic solution you can install compression fittings and garden hose fittings onto your immersion chiller. This will allow you to quickly connect and disconnect a garden hose using female garden hose quick disconnect fittings.
12.7mm compression fittings KL02004 and male garden hose fittings KL09461 can be purchased separately. Two of each fitting will be required to have a male garden hose fitting on each end of the immersion chiller.
Connecting the immersion chiller to your BrewZilla pump – Ice Bath (optional)
If you were looking to save water you can easily hook your immersion chiller up to the pump on your BrewZilla using 12.7mm compression fittings KL02004 and camlock fittings (KL04503 and KL04497). Run some silicone hosing KL06873 from your recirculation arm to your chiller and then run silicone hosing from the outlet of the chiller back into the BrewZilla.
The compression fittings, camlock fittings and extra silicone hosing can be purchased separately.
If you prefer to use this method recirculate boiling wort through the chiller and back into the boiler for at least 5 minutes to make sure the coil is hot and any potential contaminant such as wild yeast or bacteria are killed by the boiling wort.
Once you have sanitised your chiller, place the chiller into a bucket of ice water and use the ball valve on the recirculation arm to adjust the flow rate. Adjusting the flow rate on the recirculation arm will change the temperature out of the output of the coil. So, use this adjustment to achieve your desired wort temperature so the wort is at a suitable temperature to put into your fermenter.
Hot Cubing
Another great method of cooling your wort that saves time is hot cubing. If you fill a HDPE Cube or HDPE Bladder with hot wort then quickly fit the lid, this will keep your wort in a sanitary environment, as the boiling or near boiling temeprature wort is hot enough to instantly sanitise.
If you use this method, make sure to purge air out of the cube / bladder and then simply leave it at ambient temperature for 24 hours to cool down (preferably out of direct sunlight). Once cool, transfer to your fermenter and pitch yeast as normal.
Cleaning
The Gen 4 BrewZilla has a domed bottom with a centralised pump inlet. This makes it easy to drain all liquid from the brewery at the end of your brew day simply by opening the tap. After the liquid has been drain then rinse to remove any trub from the boiler. You may find tipping the unit upside down will do a better job at getting all this trub out of the boiler.
After it has been rinsed, empty this water and then fill again with water and an approved sanitiser such as StellarSan according to the package instructions. Acidic sanitisers such as StellarSan assists with dissolving minerals which produce beer stone and also helps to passivate the stainless steel. Recirculate this StellarSan solution through the camlock recirculation arm and the chiller (if required). The StellarSan solution can then be emptied ready for the next brew day, it does not require rinsing.
Pump Cleaning and Maintenance
Generally, the pump does not require disassembly after each brew day, simply recirculating cleaner and sanitiser through it will break down and dissolve any proteins, minerals or contaminants present in the pump.
The pump on the Gen 4 BrewZilla is easily accessible by simply flipping the brewery over if you decide you wanted to perform a thorough clean or your pump happens to become stuck.
If you have a blocked pump you may need to disassemble the pump. To Disassemble the pump, detach all hosing first and then unscrew the pump from the brewery. Then remove the screws that hold the pump head on and check the pump head for debris and or solids that could be stuck in the pump head. Remove the impeller and check if for damage or any blockage that could be stopping it from spinning. Look in the impeller housing and confirm no blockages are within this housing.
Pro Tip: Recirculating hot StellarClean PBW as described in Cleaning for at least 10 minutes will help keep the impeller and pump head from becoming sticky or clogged.
NOTE: Never direct a garden hose down the pump inlet or recirculation arm as this can result in the silicone hosing rupturing due to the high pressure of mains water.
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