We are going to look at some mash thickness tips I’ve picked up over the years as a brewer. We’ll take a deep dive into this subject; giving you better understanding to hopefully improve your recipe formulation capabilities.
Having a better understanding, will give you more control of the brewing process. The main points to consider when you mash in on a brew day, are:
- Your target mash temperature
- Type of grains being used – whether a lot of adjuncts are included
- Interplay among enzyme activities
- And of course, mash thickness
- Mash pH, the ideal range for most beer styles is between 5.2 and 5.5
Mash Thickness Tips – Liquor to Grist Ratio
When brewing the water is called “liquor”, and most water used on brew day, comes from your hot liquor tank (HLT).
When brewers talk about mash thickness, they use the term “liquor-to-grist ratio”. This is the volume of (liters) to the mass of malt and other grains used. The typical range when commercial brewing, is between 2 and 4 liters of water for every kilogram of malt used.
Most brewers aim for between 2.5 and 3.2 liters of water for every kilogram of grain. For our American brethren, they may use “quarts per pound”. The typical ratio is 1.25 quarts of water per pound of grain.
What Type of Mash Program Are You Using?
There are two main ways you can mash a brew.
Step mash – Where you start with a lower mash temperature and during the stand increase the temperature of the mash.
Infusion mash – You aim to mash in at a target temperature, and no heating of the mash takes place during the mash stand.
Yes, we are aware decoction mashing is also used in some parts of the world. However, that’s a subject for another day.
Which mashing technique used, depends on your equipment and what type of beer you plan to brew. For instance, many traditional UK breweries, they have no way to heat the mash tun, therefore step-mashing is impossible.
The reason for step-mashing is to help the brewer. For example, a mash stand at certain temperatures will help break down beta glucans (the gummy parts of the cell wall of malt), break down mash proteins or lower the pH.
Evidence suggests performing part of your mash stand at 43-45°C (109-113°F) will increase the ferulic acid in the wort. Which is a precursor to clove. If you plan to brew a wheat beer or Hefeweizen this can be desirable.
Whichever, mash program you follow, may determine your desired mash thickness. Infusion mashes tend to be a little thicker than step programs. Having a thinner mash when step mashing; makes mash mixing and transfer of the mash to the lauter tun easier.
Although John Palmer in his book How to Brew says “A thick mash is better for multi-rest mashes because the enzymes are not denatured as quickly by a rise in temperature”.
More on this subject later. However, as you can see, as with many subjects in brewing, “best practices” are often up for discussion.
Mash Thickness Tips – The Factors at Play
Your liquor-to-grist ratio governs the strike temperature needed to hit target mash temperature. I’ll try to keep this simple, but we need to consider the “mass energy balance”.
We’re working with the first law of thermodynamics here; “energy can neither be created or destroyed”.
Essentially, the final temperature of the mash is determined by the temperature and mass of what’s used – malt, other grains, water and any salts or adjuncts.
To hit you target temperature we need to consider the following:
- What’s your target mash temp – Determined by style of beer being made and yeast used.
- Volume of strike water – More water often used in step-mashing
- Temperature of your strike water – Set temp of the HLT. Plus, if you’re using cold water in the mix to hit desired temp.
- Heat capacity of water* – See explanation of heat capacity below
- Temperature of the grist – Can vary slightly throughout the seasons
- Heat capacity of the grist* – See explanation of heat capacity below
* Heat capacity is the amount of energy required to raise the temperature of a substance by one-degree Celsius.
This I feel is becoming to complicated. So, let me try and explain it in real terms, how brewers hit their desired mash target temperature. Honestly, as I was saying to a client on a WhatsApp call yesterday, it’s mostly trial and error.
When starting on a new system there’s some guess work. However, we can make the guess “more educated” if we use the knowledge we have at our disposal.
Mash Thickness Tips – Hitting Target Temp
As we’ve determined your first brew on a new system is always going to be somewhat a leap into the unknown. This applies to even the most qualified of brewers. However, we can as I say, make these guesses much more “educated”.
How Does Your Liquor-to-Grist Ration Affect Mash Temperature?
If your mash is “thicker” so, you’re using less water for every kilo of malt added. The strike water has to be of a higher temperature. There are mash temperature calculators one can use.
However, having the knowledge yourself, will make you a better brewer. It’s always good to understand the why. So, if there ever any issues, you have a better chance of fixing the situation.
As we’ve said before the malt used doesn’t change much in temperature throughout the year, usually being at room temp 10 to 35°C (50 to 77°F). It’s the temperature of the water and liquor-to-grist ratio which you need to consider most.
What’s The Typical “Temperature Loss”?
On average “you lose” around 5 to 10°C from your strike water temperature, to get your resulting mash temp. So, if you’re strike water is say 75°C (167°F), the final mash temperature could be between 65 (149°F) and 70°C (158°F).
If you have a thicker mash, the temperature of the water needs to be higher. As each liter of water “works harder”, to bring more grain and the overall mash to the target temperature.
So, if you’re trying to squeeze a high gravity beer, like a pasty stout into your mash tun. You’re liquor to grist ration will be lower (2.5 or below). If that’s the case then the temperature of the strike water needs to be higher.
Please note: Before mashing in always pre-heat, you mash tun/mash mixer. Use hot water through the spray ball.
This will allow the mash tun to be the roughly the same temperature from mash-to-mash, irrespective of the time of year. It removes a variable from your calculations.
Record As Much as You Can on A Brew Day
I’ve written over 100 articles on my website now; and one theme runs through many of my posts. You should record as much data from your brew, as you can. Especially, when doing the first brews on a new system.
As we’ve said there’s some guess work when brewing on a new system, due to many unknown variables. However, like this article on mash thickness tips, if you record data like:
- Temperature of the strike water
- Amount of malt used (types and % of the mash)
- Liquor-to-grist ratio
- Mash-in start and end times
Over time you’ll have records to refer to, and thus take away much of the guesswork from hitting your target mash temperature on subsequent brews.
Mash Thickness Tips – Alpha plus Beta Amylase and Mash Thickness
When you mash-in, you’re converting starches in the grain to sugars. There are two main enzymes responsible for the degradation of starch into fermentable sugars and dextrins (which are non-fermentable).
As ever the thickness of the mash goes a long way to determine, how these enzymes behave in the mash. These two enzymes are alpha and beta amylase.
Alpha amylase cuts up the starch molecules at various points along their length. It results in the production of dextrins and some fermentable sugars.
The beta amylase then takes these fragments of the original starch molecules clipping off maltose units from one end.
This is done in a very precise way, one maltose molecule at-a-time. So, during the mash stand (typically a minimum of an hour) alpha amylase produces more dextrins, leaving the beta amylase more substrate to work on.
Working in Concert
These enzymes work in concert. However, they behave differently in response to differences in mash temperature and thickness. Alpha amylase preforms better between 65 and 70°C (149 and 158°F), while the optimal range for beta amylase is between 52 and 62.2°C (126 and 144°F).
The net result is, higher mash temperatures lead to less fermentable wort. Because alpha amylase is a lot more stable than beta amylase at those higher temps.
It results in less production of maltose, as the activity of the beta amylase is diminished. I can’t give you an exact temp at which beta amylase activity drops off. Why? Because it’s also affected by mash thickness too.
The thicker your mash, the better for beta amylase activity. Explained by beta amylase being more stable when it’s joined with its substrate than when it’s not. When beta amylase encounters less substrate in a thinner mash; it’s much more likely to destabilize and become inactive.
I’ve had to simplify this explanation as pH also plays a role too, in the activity of alpha and beta amylase. To learn more about pH and mash, please read our article here. Also, there are other variables like calcium, which helps stabilize alpha amylase at higher temperatures.
Mash Thickness Tips – Conclusions
As with most processes in brewing, mash thickness and its effect on the final beer is connected to variables like temperature. The main takeaways when thinking about your mash are:
- Preheat your mash tun/mixer to eliminate one variable
- Thicker mashes require a higher strike water temperature
- Beta amylase works better at higher temps, when the mash is thicker
- At higher mash temperatures 68°C+ (154.4°F) you get less fermentable sugars
- Always record brew day data, being able to refer back to it takes out the guess work in subsequent brews
There we have it. I hope these mash thickness tips have given you a deeper understanding of what’s happening when you mash in on a brew day. As we say having a better understanding makes you an improved brewer.
Giving you the tools to react to correctly when issues arise; as well as go deeper into the parameters of recipe formulation. As ever if you have any questions or feedback, please feel free to comment below or send me a message.
Likewise, I’m brewing consultant so, if you need help with you brewing processes, sourcing equipment or setting up a new brewery please reach out. My email address is:
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Have a great day and happy brewing!