Sparging is often an essential process in brewing and the very first breweries adapted this method to get the most sugar from the grain.
Although sparging plays an important role in brewing and it’s a regular part of the processes in commercial breweries today, if you homebrew by the BIAB method, the priorities change. So, should you also sparge if you brew BIAB?
You shouldn’t do traditional sparging when brewing in a bag (BIAB) because BIAB is a method that simplifies the process of brewing and combines mashing and sparging while the grains are in the bag. This means you don’t have to mash out to stop enzymic activity, recirculate and sparge like it’s the case with the traditional brewing method.
Yet, you should still pour some water over the bag and squeeze it to extract the extra sugars from the bag after mashing.
So, you can consider this act a BIAB sparging, but the term sparging originates and is used in a traditional brewing process which BIAB isn’t.
BIAB is, after all, the modern technique that got invented for the purposes of homebrewing in the 20th century.
What’s the purpose of sparging?
The purpose of sparging is to wash out all sugars from the grains after the mashing, so you can collect them and transfer them back into the kettle with the rest of the wort. This way, brewers don’t lose efficiency and always extract most sugars from the grains which are essential for original gravity and eventually the quality of beer.
That said, when you BIAB you raise the temperature to 145°F-155°F (63°C – 68°C) for an hour to convert sugars from the grains into an edible for your yeast. Being closer to 145°F creates more fermentable sugars and being closer to 155°F leaves more residual sweetness due to a lesser fermentability which is good for certain styles that shouldn’t end up too dry.
After mashing, you squeeze and wash the bag with water you also use to top up the quantity of beer in the kettle. This is how “sparging” works in BIAB, so there’s no need for any other sparging method or anything else because you’ll then simply raise the temperature to the boiling point and keep it there.
How to do sparging with BIAB
Now, although the BIAB method simplifies the process and has excellent efficiency (you can easily have around 80% efficiency with it) there are still a few tips to get the most sugars from the grains in the bag.
We’ll call this BIAB sparging as it essentially has the same purposes as sparging in traditional brewing methods used in breweries.
1. Squeeze the bag
Squeezing is absolutely necessary if you ask me, without squeezing you can’t access the trapped sugars in the bag and sometimes the bag can contain 1/2 gallon of precious wort or more depending on how much you brew.
Hanging the bag above the kettle and letting it slowly drain is a slow and non-effective way, so using some force by squeezing the bag from the sides is important.
The advocates against squeezing the bag say you’ll extract the tannins hidden in the husk which can give the beer an astringent taste. While it’s true that there are tannins in the hush, you won’t release them into wort by squeezing because tannins are only released by temperatures above 167°F (75°C) and when the PH values of the water are higher than 5.8.
After the mashing is done, neither the temperature nor PH of the water should be in the range that will extract tannins and if the PH for some reason is still that high you’ll get the tannins out from the bag during mashing anyways, so as long as the recipe and ingredients are fine there’s nothing to worry about.
I have explained more about brewing bag squeezing in my other article, so check it out if you have more questions.
2. Wash the grains with water
Squeezing is the most important step, but it doesn’t always extract all sugars from the very first attempt. Thus after squeezing, I always pour the water I’d use for topping the wort, over the grains in the bag. Simply open the bag and pour water over it, the water doesn’t have to be warm but it can be, there’s no difference as the only goal here is to wash the sugar blocks stuck between husks.
This step is super fast but you’ll need some assistance from someone as you’ll need to open the bag and pour the water over while the bag hangs above the container which collects the wort.
I also squeeze the bag another time after this just to get the best possible efficiency and that’s it, the wort is ready to be boiled!
What if you didn’t hit the desired gravity?
The whole purpose of doing the mentioned is to achieve the best possible efficiency by extracting the available sugars from the grain.
However, sometimes this doesn’t go the way you wanted and you don’t manage to get the desired efficiency which means that one of the following happened:
- You spilled too much wort outside the kettle
- The mashing temperature was off
- The grains weren’t properly crushed
While it’s easy to spot that the reason for low efficiency could be too much spilled wort outside the kettle, the mashing temperature and the quality of milled grains can be trickier to detect.
How to control the mashing temperature
You’ll need to keep the mashing temperature between 145°F-155°F (63°C – 68°C) to extract the sugars, sometimes the thermometers don’t give us accurate readings due to the large volume of wort which gets heated at the bottom but is colder at the top.
This is usually the case with those 5-gallon batches I make, so I can’t control the exact temperature as I could if I had professional brewing equipment.
The good news is that you don’t need to be perfect at this, just try to keep it as close to the anchor point for as long as you can.
You should stir the wort during the mashing to push the liquid from the bottom up and to assure the temperature is even during the whole process.
This should improve the quality of temperature control, now we only have one problem left.
Get the perfectly crushed grain every time
The grains don’t always arrive perfectly crushed as it greatly depends on the store you are getting them from.
A few times I had poorly crushed wheat malt and I’d get terrible efficiency as the sugar simply can’t escape from the husk unless the miller did the proper job.
To counter this, pay attention to how well crushed are the grains before beginning to brew and in case they are not on point, return them to the miller for another session.
Moreover, you can buy a grain mill (paid link to Amazon) and crush your grains which will increase quality control and allow you to store the grains for longer until you need them.
Add DME or sugar to hit desired gravity
Sometimes it’s too late to adjust the process, so you need an alternative to fix things and hit the desired gravity.
To achieve this, it’s best to add DME (dried malt extract) to the wort as it’s the easiest solution for increasing the gravity without ruining the taste.
You can also add any type of sugar such as corn sugar, plain table sugar, or honey but all these sugars will impact the flavor in higher amounts which may be not desired for the recipe you are brewing.
Moreover, most of these sugars thin out the body of the beer due to high fermentability which will make the beer thinner, yet more alcoholic.
DME simply fixes the problem by increasing the gravity and acts just like any grain you use in the recipe.
How efficient is the BIAB method?
While other brewing methods require multiple kettles, such as for mashing and boiling, involve multiple tasks such as mashing out, sparging, recirculating wort with a pump, or require a whole brewing rig to be installed, BIAB tells you to take one brewing kettle, a bag and shorten everything into no more than 3 steps.
BIAB saves time, energy, and space while the quality remains either the same or even better because there is less room for mistakes. Regarding efficiency (how much OG you get from the grains) no system will yield 100% results, but you can easily claim 80% brewhouse efficiency with BIAB just like with other methods but with less hustle.
BIAB is my favorite method for brewing beer, it’s the method I recommend for everyone and hear people have the best success with.