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Batch Sparging Temperatures


Jesse McConnell - Fort Collins, Colorado asks,

When batch sparging, is it the sparge water that should be at my mash out temperature, or is it the grain bed that needs to be at my mash out temperature?


This question is a bit more about semantics than any real issues with sparge temperature, in my view of things. Bear with me while I explain how commercial brewers normally mash out and sparge. Most commercial brewers use stirred mash mixers for mashing and raise the mash temperature to about 168 °F (76 °C) before pumping the mash to the lauter tun. When sparging ensues, the water temperature is normally controlled to about 168 °F (76 °C). These procedures vary among breweries, but in general this is how things are done. The practical reason for controlling sparge water temperature instead of monitoring the grain bed temperature is because measuring and controlling water temperature is easy and reliable, whereas measuring and attempting to change the grain bed temperature by changing the sparge water temperature is neither easy nor reliable. Lauter tuns have raking machines that cut the grain bed and rarely have temperature probes installed to monitor grain temperature because there really is little use for measuring the grain bed temperature during this relatively short process.

OK, let’s move into the homebrewing realm and discuss infusion mashing for a moment. In the infusion mash tun there is no practical way to stir the mash and increase the mash temperature as with a mash mixer. This is why the name “infusion mashing” is often more completely described as “single-temperature, infusion mashing.” Brewers who use infusion mashing often times use the same basic brewing rules as those who use stirred mashing and sparge with 168 °F (76 °C) water because they do not want to run the risk of extracting tannins from the malt husk with hotter water. The truth is that hotter sparge water can be used since it is the temperature of the whole that is important when it comes to solubility.

When you batch sparge you don’t control sparge flow rate like the typical continuous sparging set-up, but the temperature control methods are the same; sparge water is heated in a single hot water tank to the desired temperature or very hot water and ambient water are blended in-line as the water flows into the sparge line. If you are an infusion masher (no mash off used) and would like to add a few levels of complexity to your rig, you could measure the wort temperature as it exits your mash tun and use hotter water to bring the wort temperature up to 168 °F (76 °C). After this temperature is hit, you would then want to finish the sparge with 168 °F (76 °C) sparge water. As I write this, the process engineer in me cringes since this is a veritable control logic train wreck for a reason I am not sure the average small commercial brewer or homebrewer is likely to not be able to justify from an economic or flavor perspective. I hope this answer has given you some information to fine-tune your sparging technique.

Response by Ashton Lewis.