Sure, the ingredients are extremely important, and you’ll need good quality malt, hops, yeast and water to lay the foundation for an excellent Kölsch recipe.
But a good recipe doesn’t brew good beer. You brew a good beer.
And it’s how you brew that determines the outcome of your beer.
Your processes, techniques, and the music you listen to when you’re brewing all play a role. Ok, the last one’s contestable, but I’m pretty sure my recipes would take a beating if I swapped Motley Crue or some Bieber!
And some of them will be shite!
So in order to brew good beer, you’ll need to dial in your brewing techniques and processes.
In this post, you’ll learn about the mash. In particular, you’ll come to understand what it takes to achieve a crisp, dry Kölsch.
Mash, Mash, Baby!
What is mashing?
Mashing is when malt and water are mixed (mashed) together at a specific temperature.
During this process, insoluble substances, such as starch are degraded (broken down) into soluble substances, such as sugar, by enzymes. The two enzymes discussed in the article are alpha amylase and beta amylase, both being incredibly important when you brew a Kölsch (or any beer for that matter).
The soluble substances in the mash are collectively referred to as the extract, and are converted by the yeast into alcohol.
If you want to learn more about fermentation, I’ll be discussing it later in this series.
The Three Stages of Degradation
No, I’m not talking about the way that your spouse treats you!
I’m talking about the three stage process called degradation, during which starch is broken down into soluble sugars.
The stages are as follows:
Gelatinisation occurs when you add your strike water.
At first, starch granules are packed tightly together, and the enzymes have a difficult time converting them into sugars.
When you add the strike water, the starch granules soak up the water, expand, and eventually burst.
Due to this expansion, the starch molecules are set free into viscous solution and are easily attacked by the enzymes (Kunze 2004).
In other words, gelatinisation makes it easier for the enzymes to convert the starch into sugars. The gelatinisation of malt occurs at around 60c.
During liquefaction, the alpha amylase enzymes break apart, or cleave the long chains of glucose molecules.
By doing so, smaller chains called dextrins are formed. Other chains are also formed, but dextrin is the most important for the purposes of this article.
At this point, the once-gelatinised wort becomes less viscous and ready for the final stage of degradation.
It’s during this stage that the beta amylase enzyme really picks up its game.
It does so by snipping off two molecules of glucose at a time from the non-reducing ends of the dextrins that were formed during liquefaction. These groups of two are known as maltose.
Meanwhile, alpha amylase continues to act by chopping up any remaining long chains of glucose, exposing more non-reducing ends for the beta amylase to convert into maltose.
Given the right conditions, this process continues until all of the starch is broken down into maltose and dextrins.
Saccharification is complete when all of the starch has been converted (degraded) into maltose and dextrins by the amylases (Kunze 2004).
Enzymes and Wort Composition
Now that it you are clear on what the enzymes do, its important to understand how to control them.
When you control the activity of an enzyme, you control the wort’s final composition. That is, you control the proportion of maltose and dextrins in the wort.
As a Kölsch brewer, you want to aim for highly fermentable wort. Highly fermentable wort will ferment down to a low final gravity, giving you a crisp, dry Kölsch.
Beta amylase, as explained above, cleaves two glucose molecules from the ends of the dextrins, forming maltose. This is good, because maltose is highly fermentable. Left unchecked, and too many dextrins will leave you with a Kölsch that it not to style. A dextrin rich wort is better suited to, for example, a Stout.
As such, you want to encourage beta amylase activity in the mash to achieve a highly fermentable, maltose rich wort.
4 Factors That Encourage Beta Amylase Activity
Mash pH, time, liquor to grist ratio and temperature all play a role in encouraging beta amylase activity.
And what does a highly fermentable wort give you? A nice, dry Kölsch.
In the Secret to Excellent Kölsch Recipes, I touched on mash pH and explained that you should aim for a mash pH of 5.5.
This is because beta amylase is most active in a mash that has a pH value of 5.4 – 5.5. A mash pH outside of this range will reduce beta amylase activity, resulting in a less fermentable wort (Kunze 2004).
The duration of the mash should also be taken into account. Although beta amylase activity peaks at approximately 10 minutes into the max, it reduces in a linear fashion as time progresses.
Therefore, by increasing the mash duration the maltose content will increase (Kunze 2004).
Liquor to grist ratio is an interesting point of discussion.
Of late, many brewer’s adopt ‘no sparge’ method of mashing. By doing this, they add all of the water to the mash at once without reserving any for a traditional sparge. This results in a very high liquor to grist ratio (AKA a thin mash).
Surprisingly, whilst there will be more extract in solution in a thin mash, a thick mash will protect the enzymes from rapid thermal inactivation.
Consequently, A thick mash results in a higher level of fermentable sugars (Kunze 2004).
Of all factors affecting the fermentability of the wort, temperature is the most important.
By mashing between 62c and 65c, you trigger the temperature range most favourable to beta amylase activity.
If you’ve stuck with me up until now you will no doubt know that beta amylase is responsible for degrading starch into maltose.
As such a temperature rest between 62c and 65c is essential.
A Brief Recap
To summarise the above, you can dial in your mash profile and dictate the wort composition.
You do this by restricting the mash pH, time, liquor to grist ratio and temperature to a specific range. This range will depend on the enzyme you are targeting.
For Kölsch, you want to restrict these parameters to a range that targets beta amylase activity.
beta amylase is responsible for maltose production.
Because maltose is easily fermentable by yeast, you will be left with a low final gravity beer with a dry, crisp finish. Hurray!
Designing Your Kölsch Mash Profile
Using the information above, you are ready design a mash profile.
Fortunately, these can be as basic (or as complicated!) as you want them to be. Generally, my best Kölsch recipes utilize a simple step mash procedure.
First, I rest the mash at 62c for 45 minutes. This gives the beta amylase time to do its work, and generate maltose rich wort.
Second, I raise the temperature to 70c for about 15 minutes. This encourages alpha amylase to break down any left over dextrins into smaller, more fermentable sugars.
Lastly, I raise the temperature to 78c to conduct a mash out. The mash out stalls any enzyme activity, and locks in the mash profile. Without this step, replicating the mash profile in future brew sessions would be very difficult.
And now, it’s time for the boil. I’ll be discussing this in the next post.
Do you have a favorite Kölsch mash profile? I’d love to hear them, so please post a comment below!
Kunze, Wolfgang, and Trevor Wainwright. Technology Brewing and Malting. 3rd Rev., International ed. Berlin: VLB, 2004.