All-In-One System Designs
TroubleShooting
Luiz Rebouças • Via email asks,
By reading one of your explanations on “simplifying brewing” I understand that you use a Grainfather all-in-one brewing system. I have used the Grainfather G30 for about eight years. From the very beginning I was upset with the non-homogeneity of temperature during mashing. Because the temperature measurement position is located under the false bottom, I have concluded that the wort atop of the grains is much cooler (confirmed by measurements with an external thermometer). I saw that the grain tube in the new Grainfather model has perforations on its cylindrical surface, so I am updating my system with a new basket. Though I question whether part of the wort will not be flowing through the grain with this design and the efficiency will be severely reduced. What is your opinion on this?
Luiz, thank you for the great question. I do brew using a Grainfather G30 and am familiar with how the original system is designed, as well as the new basket. For those of you who are not familiar with these systems, there are two main parts of the Grainfather and other systems based on the same basic all-in-one design (see diagrams shown in Figure 1).
The brew kettle is heated from the bottom using an electric heating element positioned on the bottom of the kettle from the exterior. When looking down into the kettle, the heater is not visible. When used for mashing, a smaller mash basket is inserted into the kettle to hold the mash. In the original basket shown on the left in Figure 1, wort flows down through the bottom screen, into the pump and is returned to the mash basket onto the top screen. Wort pooling above the top screen flows directly to the bottom of the vessel through an overflow pipe to prevent the pump from exerting too much pull on the mash and from starving after all wort outside of the basket has been pumped to the top.
In my experience, the original design works best when using coarsely milled malt or more finely milled malt in conjunction with rice hulls because the mash bed is more permeable. The issues I have experienced with the original design are variable yields, occasional long wort collection times, and difficulty with uniform mash temperature. This sounds like your experience.
One thing that works for me is to start my mash at about 140 °F (60 °C), periodically stir for about 15 minutes, then install the top screen, and start the recirculation pump and the mash profile. If I am using a single mash temperature, I start my mash at about 149 °F (65 °C), periodically stir for 15 minutes, install the top screen, and start the pump and simply set my mash temperature at 149 °F (65 °C) to maintain temperature. Mash stirring during the beginning of the mash really helps with thorough hydration of the malt while also moving things around to improve extraction. I spent my commercial brewing days using stirred mashes and really like the yield improvement and increased consistency between batches that stirring provides.
To answer your questions, I contacted Aaron Hyde with RahrBSG to get some information about the new basket design used in all new Grainfather systems. Aaron is currently RahrBSG’s Director of Product and Portfolio and the former General Manager of Portfolio and Strategy for Bevie, the New Zealand-based company that produces the Grainfather. The basket redesign was Aaron’s brainchild.
“I suspected side perforations would improve temperature control because the perforations improve wort flow through the mash, even when thick and sticky, which is why the overflow pipework on the old system was needed.” Aaron also felt that adding side perforations would not decrease efficiency because liquid tends to flow down through the grain bed during draining. In practice, users of the new design report higher yields in comparison to the old design and find the new design to perform more consistently from brew-to-brew.
One thing to consider is sparging technique. Some brewers like to keep a small volume of water above the mash bed during sparging and time additions or the flow rate of continuous sparge additions to maintain a consistent level of water. With the new design, that method would indeed result in water flowing out of the side perforations. The best approach to sparging is to add sparge water in batches until it just begins to pool. After a couple of minutes of draining, add more sparge water.
The larger models are equipped with a sight tube showing wort volume in the kettle, while the G30 does not have this feature. I use a calibrated wooden stick (flat yard stick purchased at the hardware store) with my G30 to monitor how much wort I have collected and use this information to gauge when more sparge water is needed (to use this stick, I slip it between the kettle and grain basket wall and look for the top of the wetted portion). For example, if adding sparge water in 2-quart (2-L) increments, waiting for the kettle volume to increase by 2-quarts (2-L) indicates when the next addition can be made.
I do think that the questions posed make sense, but at the end of the day, the improved liquid flow through the bed during wort recirculation outweigh the small volume of wort flowing outward from the perforations.
