Sparge Water Temperature

The short answer to this question is no, sparging at 169 °F (76 °C) does not achieve the same thing as mashing out at the same temperature. The reason for this is two-fold. Let’s assume an infusion mash system comprised of 10.4 L (kilograms) water and 4 kilograms of malt (1.25 qts. water per pound of malt) at a temperature of 153 °F (67 °C) is mixed with all 19.6 liters (5.2 gallons) of sparge water at 169 °F (76 °C) required for the brew; assuming no energy from the sparge water is lost to the environment, the resulting mash temperature will be 163 °F (72.6 °C). Not only is this temperature much lower than the typical mash out temperature of 169 °F (76 °C), but this temperature is not possible until all of the sparge water has been added during the course of wort collection. And the reality is that temperature loss to the environment does occur and the mash will never reach the calculated temperature of 163 °F (72.6 °C). Is this significant and relevant to your question? Yes, and it brings up the second point to this answer.

Modern malted barley is an enzymatic powerhouse and the high enzyme level is generally a property of malt that has been very well-modified. Roll back the brewing clock about 25 years and this description of malt would have been believable if the conversation were about North American malted barley; however, malts from continental Europe and the United Kingdom were a bit different, both in terms of modification and enzymatic power, and the same description would not have been a good fit. But in the modern world of brewing, enzymatic power and full modification has become the norm. Why? Because brewers want malts that quickly and reliably perform in the brewhouse with simple mash regimens, and many brewers want malts that can handle enzyme dilution from adjuncts. This means that all-malt brewers need to pay careful attention to these “hot malts” because the high enzyme level and the high degree of modification may result in overly dry beers if the mash is too long.

The normal practice for many commercial craft brewers in the US using the infusion mash method, is to mash-in, quickly begin wort recirculation, aka vorlauf, and begin collecting wort in the kettle as soon as wort clarity is achieved. Since infusion mashing does not employ a mash-out step, enzymes from the mash continue activity in the kettle until the wort temperature is sufficiently high to cause the enzymes to denature. For this reason, it is common for brewers to begin heating their kettles as soon as possible following wort collection. This also reduces the length of the brew day, but that’s just a fortuitous consequence of the main objective. In conclusion, I suggest mashing out if your brewing system allows you to do so easily, or using an abbreviated mash schedule if you want to brew a beer with more residual sugar. And, of course, you can always seek malts that are not so darn hot!

Response by Ashton Lewis.