Lesson 4 - The Mashing Process
This lesson discusses the process of mashing. It provides an overview and sets out the objectives of the process before explaining what parameters need to be controlled to ensure success. It describes the various methods used to mash and their impact on the wort produced. Finally, it details the composition of wort produced by mashing.
Overview of Mashing
There is no such thing as a standard mash. Today’s mashing practices have evolved from earlier mashing procedures that were developed across the world to get the best out of local raw materials. So as brewers, we have a range of mashing options. Before we get into these specifics, we will outline the activities we find in the various methods and then the various parameters we can influence to achieve success.
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Grist hydration – water is central to everything we do in mashing, so it should go without saying we need to mix grist and water together. As we will find out in the next lesson, there is a fairly wide range of approaches to this. The degree of hydration at the start of the mash depends on the technology being used for milling and mashing.
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Mashing in – at mashing in, we fill the mashing vessel with hydrated grist. In some very small operations, dry grist is tipped into a vessel full of water and stirred, but these are the exception, not the rule.
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Mixing – at this stage, the contents of the mashing vessel are mixed. In isothermal mash tuns, the mash is mixed only by the action of filling the vessel. For all other types of mashing, an agitator stirs the mash to ensure hydration of the grist particles is complete.
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Heating – if mashing is undertaken at a range of temperatures, it is heated. While it is heated, it is stirred to ensure the heat is distributed evenly throughout the mash. Heating is undertaken to raise the mash temperature to a set point over a defined period of time. This is sometimes called ramping. In some mashing regimes, the mash is heated by adding hot water or mash that has been heated in another vessel.
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Stands – after mashing in or heating, the mash is left to stand for a period of time at a target temperature. During this time, any agitation is turned off or maintained at a very low speed. For mashing where more than one temperature stand is used, at the end of the stand, the agitators are sped up (or turned back on), and the mash is heated again.
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Mashing off – if wort separation is undertaken in a different vessel, a final heating step heats the mash to the temperature required for transfer.
We will meet each of these elements later in the lesson when we discuss each of the methods of mashing. It is important to keep these in mind in the next part of the lesson, where we detail the parameters that affect the outcome of the mashing process.