Some questions seem ever-repeating and people who ask whether they should squeeze their bag or not seem to never get a final answer.
Well, it’s time to answer this once and for all, back it up with some facts, and explain every single thing that may be planted in your mind when you ask this question.
I do understand that you only want the best for your brew, so listen to this.
Squeezing a bag is not necessary, but it can be done without worries that it will hurt your homebrew by any means. As a matter of fact, many brewers including myself recommend that you squeeze your bag because this way you’ll not waste the liquid and will get the most out of the grain.
Let’s see why is that so.
Why do people say squeezing a bag is bad? (Debunking a myth)
The advocates against squeezing a bag say that it may release the tannins from the grain which can impact the taste profile of your beer.
However, this is not true by any meaning because tannins won’t magically escape into the wort by the touch. Let me explain what the tannins are and what makes them escape the grains.
What are tannins?
Tannins are compounds found in grain husks, bark, wood, leaves, and many fruits such as walnut, cranberry, grapes, cacao, and many more. Their purpose in nature is purely protective as it makes them undesirable meals for animals. They are not desirable in most brews, but they are the reason for a distinct taste of wine in which case they are quite desirable.
What do tannins taste like?
Tannins cause that astringent sensation in your mouth which is often confused with the bitter taste, yet it’s just a sensation. The astringent sensation doesn’t always have to be uncomfortable as some tannins may give an elegant touch to a wine.
In our case, we don’t need tannins in beer as it’s something seen as undesirable, so unless you want tannins purposely in your beer, do not introduce them into one.
For a better picture of what tannins taste like grab a bag of tea and suck it for a minute. You’ll be left with a drying mouthfeel with a weird sensation.
When do tannins escape from the grain husk?
As you’ll see if either of the following cases is an issue, then your beer will be full of tannins whether you squeeze the bag or not because while the bag is in the water the tannins can easily escape if allowed so. So, in either case, the squeezing of a bag won’t be a problem.
1. The Ph factor
The tannins will only escape the grain in two cases. The first is when they are found at a pH above 5.8 during the mash, moreover, they are most stable between 6 and 8 pH.
You shouldn’t have a problem with pH values if you use good, safe-for-drinking water. The safe bet is to use distilled water as it has a pH of 7.0. Most municipal waters may have a slightly higher pH above 7.0 due to the natural minerals found in them and although this water can often be used, some municipals don’t have the finest water, so if you think that’s the case with where you live, stick with the distilled water.
During the mash you want the wort to be between 5.2 and 5.6 ideally. Adding grains will drop the pH from 7.0 down to the desired range between 5.2 and 5.6 in most cases because the grains are acidic compared to the water.
Unless there is something wrong with the recipe or you have terrible luck with your municipal water there shouldn’t be problems with the Ph of your wort.
However, it’s possible to increase the acidity by adding more dark roast malts as they are always more acidic compared to the pale malts or you can add lactic acid. You can use a pH meter or strips to check the pH of the wort or water, so if you find out that this is by some chance causing you trouble with your homebrew, you’ll be able to adjust.
2. Temperature issues
The second one is when the mash temperature is too high (above 170°F) as the enzymes react differently depending on the temperature.
It’s important not to let the temperature go beyond this point as it will allow the tannins to escape, so if you can’t control the temperature pull the bag out and return it when the temperature is under control again.
You can use cold water to quickly drop a few degrees in a wort if the heat reduction doesn’t work fast enough.
Why is bag squeezing recommended?
If these previous factors are not an issue, the bag squeezing will come with advantages that will make your beer better. There will be always trapped grain juice within the bag that can’t be drained out any other way but by squeezing it. In my case, I can drain more than 0.5 gallons from the bag by squeezing it tightly, so imagine how much precious juice would otherwise be lost. The juice is good because it contains the best out of the grains and by no means extracts the tannin in the right conditions.
However, be careful not to accidentally drop pieces of grain because they might end up in the beer later, so always use a bag with small holes that do not leak chunks of grain.
How do you squeeze a brewing bag?
Bag squeezing might not seem like rocket science but a few simple tricks will help you do it almost effortlessly with maximum efficiency.
When I squeezed my bag for the first time I brewed with the BIAB method, I left with the red, burnt skin on my hands and with the kitchen floor full of sticky wort. Basically, I was hurting myself for the science as I had in my mind that day. I just couldn’t let some pain ruin the process of brewing BIAB after planning it for weeks and gathering ingredients.
Hopefully, my friend was there to assist me and burn his hands too, so at least the misery loves company.
This could have been easily avoided if we only used gloves. However, the plastic, medical gloves won’t help against the heat, so you’ll need those working gloves with thick gum or something similar that protects against the heat.
Secondly, forget about pressing it with a spoon or some kitchen gadget, the hands are the best tool as you need to squeeze and push with fingers from all sides to get the juice out.
The most helpful tip is to hang the bag above the vessel and let it hang freely as you squeeze the juice down. I had a friend who did this but the poor guy ended up with sore muscles after all 15-pound bag isn’t that light.
Whether you have help or not, I believe that everyone should hang their bag as I haven’t found a better and simpler technique to make this task effortless. Yet, you might need to dedicate some place where you can screw a nail.
As you can see in the picture above, although this was 5 gallons stainless steel cooking vessel I had a hard time fitting the bag (although it wasn’t an issue during the mash). These are the things you think in advance before buying the equipment, but yeah I am not that smart.
Anyways, when you hang the bag above it, it’s easier to aim the juices straight into the vessel, so it’s really worth investing in a nail and a rope.
Final take on
I hope you are finally convinced to squeeze the bag as this will make your brewing more efficient. You should also know that even if you decide to skip on the squeeze that you won’t significantly hurt your brew and definitely no one will be able to guess when they enjoy your beer.
Also do not forget to boil the wort for long enough after mashing as prolonged boiling can have beautiful effects on a homebrew beer.
I’ve been squeezing the bag forever since I discovered the BIAB and can personally vouch that it’s a good practice, so go in peace my homebrewing brother or sister!