Stirring is a common technique in brewing, and every homebrewer needs to master stirring to optimize their brewing processes. Yet, it doesn’t mean that stirring is always necessary because just as it helps to get better results, sometimes it can be a liability.
During my homebrewing adventure, I discovered that simple techniques such as stirring can have a tremendous effect on the final brew, so I always tell myself not to be lazy and put in the extra work.
I’ll explain why stirring matters and when it should be avoided in each brewing step, but in short how much does stirring matter, and should you stir the wort?
Stirring of the wort is essential during mashing, unnecessary during boiling, useful during cooling, and forbidden during fermentation. Knowing when to stir and when not to stir is essential to brewing knowledge.
Let’s now explain how much stirring matters in each step of the brewing process.
Should I stir during mash?
Mashing is the process where the grain starches are converted into fermentable and non-fermentable sugars.
Depending on the brewing method there can be rather a greater or lesser efficiency or in other words how well did your method convert the grain starches into sugars.
It’s unrealistic to ever hit 100% efficiency, but it’s possible to go slightly above 80% and as a matter of fact, a homebrewing standard is at least 80% which is exactly what you should follow.
Stirring can help you achieve this desired efficiency.
The worst thing to happen during mashing is to have dry spots in the middle of the grain placed in a brewing bag or between grains if you are brewing non-BIAB.
Grains can get sticky or the water may simply not reach the middle of the grain pile when you are brewing larger quantities.
Thus, you should stir for up to 5 minutes after starting the mash and stir a few more times every 10 minutes until the end if you are brewing 5 gallons or more. In case you are brewing less than 5 gallons, stir less but nevertheless do not forget to stir!
Should I stir my wort while boiling?
Boiling wort stirs itself, so it’s not necessary to manually stir at all. Yet, there are a few exceptions.
During boiling the sugars are already equally absorbed by the water and when we add hops the boiling will produce enough movement in the wort so the alpha acids from hops will nicely merge with the rest of the wort.
After boiling we’ll transfer the wort to the fermenter and shake it, so even if somehow all ingredients weren’t nicely mixed already, they will be at this point.
However, it makes sense to stir if you add lactose to the wort because lactose is added by the end and it’s a good practice to give the wort a short stirring just to be sure the lactose gets equally mixed with the rest of the ingredients in the wort.
Another situation I have in my mind is to stir occasionally if you are brewing outside where the cold wind could chill the top of the kettle or if you are brewing very large quantities in a big brewing kettle.
In such a case, stirring is a useful technique to compensate for the temperature differences in the kettle as the bottom could be warmer than the top. By occasionally stirring every 5 to 10 minutes during boiling you’ll ensure the wort is always at the same temperature which is especially important for hops that are added on top. If somehow the top of the wort is significantly below the boiling point it could impact the hops utilization.
Should I stir the wort while cooling?
Stirring will hasten the cooling of the wort and that’s a fact. Chillers work in a similar way, the cold water enters and leaves so the new, fresh cold water can always circle within the coil.
By stirring you’ll reduce the imbalances as otherwise, you’ll have parts of the wort that are colder and warmer, so it will take longer for the whole wort to cool down.
However, if you use a chiller stirring is unnecessary because the chiller equally chills the entire wort at once.
I either use a chiller or let the wort cool down overnight in which case I don’t care about the extra time required to chill the wort.
If you plan to stir to hasten the cooling process be sure to do it with sanitized equipment as otherwise, you could contaminate the wort when it significantly drops in temperature as it will no longer have the natural sanitation properties that come from the heat.
If you don’t have a chiller, here are a few methods to cool the wort at home.
Should I stir my homebrew during fermentation?
Never stir your homebrew during fermentation as it’s not only dangerous to interrupt the yeast after it activates but you may also introduce oxygen which will greatly affect the quality of your homebrew.
Oxidation is a serious homebrewing issue and we should try to minimize it. Oxidation will produce off-flavors, so the homebrew may taste stale, and give off a wet cardboard-like taste, and some brewers report flavors that resemble rotten fruit.
Oxidation won’t always result in the same off-flavors because it depends on which ingredients you have in your homebrew, but it’s never a wanted result.
When the wort is at optimal temperature for yeast pitching, pitch it, shake it or aerate it with a pump (oxygen is only needed as a nutrient for yeast at the beginning) and let it work in peace to avoid causing yeast stress or oxidation.
Stirring after dry hopping?
It’s unnecessary to stir after dry hopping because just like it’s the case with any later additions, we give it enough time in the secondary so the additions can naturally mix with the rest of the brew.
Stirring can be done to hasten the process in case you want to add some later addition like herbs or spices soaked in alcohol and then bottle because otherwise, you’d have an unequal ratio in the entirety of the brew.
If you stir for such a reason, be careful not to introduce oxygen and contaminate the brew. To achieve this, stir gently and slowly without splashing or causing whirlpools, and always sanitize any equipment that will get in contact with the brew.
Stirring after topping up with water?
Topping up the volume with water after boiling means you’ll have to stir to mix it well with the rest of the wort. This might seem obvious, but sometimes homebrewers forget to do it or take the gravity readings too soon, and then it seems the OG is off, while all they had to do is stir, wait a bit and then take the readings.
This step is done prior to adding yeast most of the time so only good sanitation measures will be necessary, but if you top up the volume after the primary fermentation is complete, be careful not to introduce oxygen by mixing vigorously.
Key Takeaways
- Always sanitize brewing equipment before stirring at any step after boiling as you don’t want to contaminate the brew.
- Stirring is useful during brewing, especially for mashing, but often unnecessary in later steps
- Don’t interrupt yeast when it begins to ferment with stirring or shaking (don’t move the fermenter)
- Stir gently and slowly not to introduce oxygen when stirring after primary fermentation is complete
That’s it, I hope I covered important topics related to stirring, it’s such a simple technique yet a very important one!
These tips are useful for homebrewers, but if you pay a visit to traditional breweries which still use techniques from medieval times you’d see there’s way more stirring involved in their methods, so it’s probably the reason why most people associate stirring with brewing as the super important practice. Today, the machines do the stirring in commercial breweries which took some spirit away from the brewing and personally I enjoy tradition and original ways, perhaps not for efficiency but for the overall experience and authenticity which sometimes can result in a better product.