BIAB Brewing Primer for Beginners

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Brew -in-a-bag (BIAB) is a full-volume, all-grain brewing process using a single kettle. The appeal of BIAB brewing to me is the great quality beer that you can make using a very simple process. In fact, if you stick with the basics, you could start brewing BIAB without ever brewing extract.
So here's a down and dirty primer to get you started. Below are the items that may be different than what you are using for extract brewing.
Large Brew Kettle

This is a 17,000 BTU burner on our kitchen cooktop. I can get a decent boil out of it if I don't feel like brewing outside.
With extract brewing, a 5-gallon kettle works well. You could brew just as easily on a stovetop as you could a propane burner. It's easy enough to handle, so a ball valve isn't necessary. With BIAB, you need a 10-gallon kettle at a minimum. Don't bother trying to get one of those 7-gallon turkey fryer kits. It's just not going to be large enough. Also, plan on installing a ball valve on your BIAB kettle. It's going to be pretty heavy when full, so with a ball valve you can transfer your wort easily and safely.

A good size propane burner is what you really need. This one is between 185,000-210,000 BTU's!
Unless you have a high BTU burner on your stovetop, you'll most likely be brewing outside on a propane burner. If you have an electric stove, you may want to see if you can get a canning burner element for it.
Large Grain Bag

Standard nylon grain bag in an optional strainer basket
Well this is the "bag" in brew-in-a-bag! You have a couple of options here. One is to simply buy a course-mesh nylon grain bag from your local homebrew supply and the other is to get grain bag specifically made for BIAB. Bags from your homebrew supply are typically 24" x 24" or 24" x 36" in size. The premium custom bags can be closely tailored to your kettle's size and dimensions. They are also typically made of polyester and have reinforced seams with sewn-in handles.

Here's a view from the inside.
Which do you choose? Start with the less expensive version from your homebrew supply. It's cheap and reusable for a few brew sessions. As you dial-in your equipment and process, you may consider upgrading, depending on your needs. Since my kettle has a basket strainer, the basic bags work just fine for me.
Double-Crushed Grains
So you can follow the all-grain recipe easily, just ask you homebrew supply to double-crush your grains. It will aid in the extraction process and allow you to order the same amount of grains that the recipe calls for. You could also add more grains to the grain bill in lieu of double crushing, but we want to keep things as simple as possible here, as we get started.

These grains have been double crushed
BIAB Water Calculator
This is another area of BIAB brewing that can get more complicated if you want it to. Basically, BIAB is a full-volume process, which means that you need to calculate how much water you need to start with and that will take you through the entire brew process. I've covered this more completely in this HBT article: Water Requirements For BIAB Brewing.

The BIAB Process Steps in a Nutshell

Here's a quick rundown of what you're going to do:
  1. Use the calculator to calculate your strike water quantity
  2. Bring that amount of water to the strike temperature you calculated. This number will be higher than the typical mash temperature of 152F to compensate for the cooler temperature of the grains before they are added.
  3. Mash your grains for 90 minutes, stirring occasionally. Your brew sheet will probably say 60 minutes, but always mash for 90 minutes to increase your efficiency.
  4. After the 90 minute mash is complete, raise the temperature to 170F. Stir the mash and let sit for 10 more minutes. This is the mashout.
  5. With the mashout complete, you simply pull the bag out of the kettle and let it drain off, or gently squeeze it. Be careful during this step - it's going to be hot.
  6. After you've drained off the bag you have your wort. Now the process is the same as extract brewing. Take your pre-boil gravity sample, record the pre-boil wort volume and temperature, then start your boil.
If you're new to BIAB, you can see how easy it is to get started with brew-in-bag. Hopefully you'll also notice the quality difference in your beer. If you take the time to calculate your equipment's boil-off rate (see Water Requirements For BIAB Brewing), you'll have a better chance of hitting your final numbers.
To see start-to-finish BIAB brew sessions videos, please check out BIAB Brewing on YouTube.
Derrick Hakim runs the website BiabBrewing.com, where he shows what he's learning about BIAB, with articles and videos that detail his entire journey through the Brew-in-a-Bag method of all-grain brewing. Derrick is also the author of Brew In A Bag - Get Mashing With Less Equipment and Steps in the March-April 2014 issue of Brew Your Own magazine.

We often forget that 5 gallon batches are not a requirement in brewing. Large kettles such as 10 gal often don't fit on one's stove top. I'd like to remind folks that a 3 gallon batch can easily be mashed/boiled in a 7 or 8 gallon kettle, which will fit on your stove. This further simplifies your BIAB brew day and lowers expenses for trying it out - no propane burner needed.
Also, cheap 5 gallon mesh paint straining bags from the hardware store work fine. It's not necessary to buy customized bags, all due respect to the purveyors of same that contribute to the forum. I've got two such bags and have done half a dozen BIAB sessions using the same one so far.
The only comment I would leave, if you have already purchased/own a 7 gallon turkey frier kettle (that you got in a kit). You can still do 3 gallon batches somewhat comfortably if you are doing no sparge. I had a 5 gallon kettle I purchased for my extract days (with top off). I can do a sort of modified dunk/pour over sparge with my 7 gallon kettle. My boils are slightly hairy before hot break but once I get to hot break I can boil the 6ish gallons I get and do 5 gallon all-grain BIAB. So if you already have it, dont worry, you can still do BIAB 5 gallon batches you just have to get creative. As they say theres more than one way to skin a cat, theres no single way to brew a delicious batch of beer.
(disclaimer: if I'm shooting for a 1.070 or greater beer I calculate the batch to 2.5-4 gallons depending on the gravity I want, 12lbs is about the max I can fit in my set up, smaller batch size, higher gravity. Partial mash is another route I take, just did a 1.108 wee heavy 5 gallon batch and came out one of my best beers yet in a 7 gallon kettle)
I'd like to suggest that it's not a sin to use top up water. I can mash and do a rinse sparge to a boil of about 4.5 gallons (extremely pushing the limits of my 5 gallon kettle), just about hit my gravity, add about 1.5 gallons of top up water, and make great beer.
It just means mashing in a cooler instead of a kettle.
Totally agree with you guys about adjusting the batch size.
Just wanted to make it very simple for a new brewer to order an all-grain recipe kit and do their first BIAB easily.
My first BIAB was with a painter strainer bag too!
I use a 7 gallon pot with a colander as shown in the pic. I do 5 gallon batches, I can mash 12# of grain and I sparge in my bottle bucket. I too use a paint strainer from HD $4.00 for two bags.
One criticism. It is NOT necessary to mash for 90 minutes. With a good double crush, I can hit my numbers in 60 easily. Usually, I overshoot my gravity. Some have ven experimented with extremely short mashes successfully. I understand this is meant for beginners, but to say that a 90 min mash is required is just not accurate.
Also, a cheap way to get a really good bag is to go to the fabric store and get a yard of polyester voile fabric. If you can sew it into a tea bag, even better. Either way, this is all you need for a bag. It is cheaper and a way better filter than the coarse bags sold by the LHBS.
@Foosier, I also overshoot my gravity and need to down size the recipe. BIAB seems to be made out as some sort of mysterious way to brew, I find it to be more efficient and easier for 5 gallon batches.
I have yet to do my first BIAB batch, but just picked up a 9G welded kettle and ordered the SS fittings for it. Going to use paint strainer bags that I've been using for partial-mash/extract brews. I've got a huge gas burner on my oven that I *hope* will have enough juice to get me a decently rolling boil.
A few things that worry me are preventing the bags from burning on the bottom of the kettle and the thermometer probe snagging the bag.
Thanks for the tip. I might try that.
"A few things that worry me are preventing the bags from burning on the bottom of the kettle and the thermometer probe snagging the bag."
Put something between the bag and the bottom of the kettle to keep the bag off the bottom of the kettle.
Don't stir the mash with the thermometer probe in the bag.
no problems...
@clockwise.you don't have the burner on until you remove the bag.i heat my water up the 70 c place bag in pot then grain,stir the grain thru to remove lumps.place lid on pot,and wrap the pot to maintain temp.after 60mins i remove the bag with the grain and you get left the wort(rest of process see the video).The whole process is not hard...you only need one vessel
One note on heating while the bag is in. It can be done without any fear if you stir constantly while the flame is on. The only way the bag can scorch is if it gets stuck to the bottom where the heat can concentrate and get above boiling. If you stir, you keep the wort flowing aroung the bag and it cannot scorch.
You definitely can stir with a thermowell, what you need to do is be sure to keep from snagging the bag on the probe. You don't have to stir like a madman, just keep the wort at the bottom of the kettle moving.
I will also add this thought... A ball valve is NOT required. I use a 10 Gal pot with no valves, ports or thermowells at all. It is simpler this way (and cheaper). I do agree with the author that moving a large pot filled with liquid is a recipe for problems, but there is an easy way. Get an autosiphon! Once my wort is chilled, I take a sanitized autosiphon and use that to move the wort to the fermenter. Works great and is super easy. Plus the autosiphon is an extremely usefull peice of equipement for transfering your beer around at other times too.
A couple more beginner tips:
1. Re: bags, no you don't absolutely need a custom bag, but at the very least your bag should fit over the lip of your kettle. My local HD doesn't stock large enough paint-strainer bags, but I've found this to be a effective and relatively cheap solution for my 16 gal kettle: http://morebeer.com/products/bag-29-brew-biab.html
2. I highly advise using a wood or plastic spoon (I use one of these: http://www.austinhomebrew.com/Beer/Stirring/Spoon-Round-Head-24-Inch.html#.VKxMnIrF-pw) to stir your mash. Metal spoons have a tendency to fray or tear the bag.
You can put a small stainless steel colander (upside down) on the bottom of you kettle during boiling. That will help to protect the bag from scorching. They make small half-round ones that work well.
The auto-siphon is a good idea in place of a ball valve. It may be a bit slower, but not by much.
I do 3 gallon BIAB on my stovetop in a 20 qt kettle. Scaling recipes is easy in beersmith, i think new brewers should be aware that you dont need to start with a 5 gqllon batch...and considering my first batch....nobody wants 5 gallons of that.
I know everybody does it, but there is no good reason to do a full volume mash with BIAB.
A high mash pH is going to be a problem for a lot of people when doing a full volume mash, especially if they have alkaline water. I believe that this is the true culprit behind the reports of low efficiency, dull malt flavor, etc many BIAB brewers experience. If you don't believe me, measure it yourself; a typical full volume mash pH will be about .4 higher than that of a mash at a 2 quarts per pound thickness
Mashing at a reasonable thickness, such as 2 quarts per pound of grain, and then topping off with water after conversion is complete is a much better way to brew. Furthermore, double crushing grain when your mash pH and thickness are more in line with a traditional setup is unnecessary, as is a 90 minute mash.
Seriously, just mash for 60 minutes at 1.5 to 2 quarts per pound, top off with water, pull and drain bag. I single crush my grain and exceed 82% efficiency this way every time.
Nice article. I do agree that 90 minute mashes aren't mandatory, but longer mashes can be beneficial and it doesn't hurt anything either. I routinely do 90+ minute mashes when I brew. Mainly because I'm not in a hurry when brewing and the longer mash time gives me extra time to have a nice long breakfast or lunch before starting the boil.
Full-volume mash is a wonderful idea in concept, but it doesn't work for everybody because you need a bigger pot. Sparging the bag in a food-safe bucket after removing it from the kettle is an easy way to increase your capacity, and a good sparge-drain-squeeze regimen will get you great efficiency. In my case, brewing 5-6.5 gallon batches on my stovetop (in a 9 gallon kettle), sparging requires more effort for me than a full-volume mash would, but I sparge while my kettle's coming to a boil anyway, so my brewday's no longer than it would be with a full-volume mash, but I get better efficiency and have greater capacity than I would if I went full-volume.
As for mash length, 90 minutes might be good, and if you're bottling another batch on brewday that's a great way to use that time, but if your brewdays are time-sensitive (I typically do a couple brews a month after work on weekdays, so I'm often STARTING at 6:30 PM), an extra half hour is a problem.
Great article and great comments. There are lots of options for BIAB brewing. This article was meant to make it as simple as possible for the beginner.
I generally choose to mash in my turkey fryer and then sparge in a separate cheap kettle.
I made a hop spider out of a Stainless food processor drain thingy and three lengths of threaded rod and a few nuts.
I wrap the bag around the hop spider until the bag is lifted out of the wort and it hangs there until the wort drains out slowly, then I dunk it in the sparge water in the other kettle and stir and then then immediately wrap it up again and let it drain more completely.
While it's draining I am heating the first runnings.
And I think it's worth noting that there is NO reason a person can't scale a recipe down to less than 5 gallons. I just did a 4 gallon recipe this weekend. A stronger beer can be made in the kettle and then top-off water added to dilute the wort and make up a larger batch as well.
I've found that biab works real well with partial boil, partial mash as well. Even a single crush in my Barley Crusher mill @ .039" & a dunk sparge stirred & sitting for 10 minutes gives higher OG's. Good article to show how easy it is. Tried 2 minute dunk sparge with stirring on the last batch. worked OK, but OG wasn't as high as last time. Although a 1.054OG against a 1.049 is still darn good.
I put up a picture tutorial run through of a first BIAB brew day for those who are interested. There is also a link to how to make a beautiful brew bag for a very few dollars.
People tend to double crush their grain or they crush it more finely to begin with. That helps with the eff % that you are speaking of. It's not that's it's mysteriously high - you're just able to get a finer crush without the worry of a stuck sparge if you are doing all-grain the conventional way.
Using a cooler mash tun and at 153 for 75mins, I usually get around 82-85% eff.
I started brewing using partial mash. Now with 8 or so batches under my belt, I want to move to all grain but the equipment and work inside my little kitchen was daunting. At the local brew club I was talking about my set up which was running a full 6-7 gallon with boil off in 10 gallon kettle and folks said, just go BIAB. Now, I have to take the plunge! Summary here was helpful so thanks. will take a look at the strike temp calculators. Next weekend is the first try. This weekend is for bottling the last batch! Will try to swing back and report on how it went.
Double crushing your grains can increase your efficiency, but might introduce tannins in your finished beer. According to Pat Hollingdale's interview w/ James Spencer on a recent Basic Brewing interview, your typical mash in a 3 vessel system is 60 minutes, but you end up spending at least another 30 minutes sparging, giving the grains even more time to be in contact with hot water. My own experiments last year confirmed that a 90 minute mash was sufficient to hit my target gravities without double crushing or adding more grain. In fact I found that my overall efficiency was 80% using this method, and overshot my gravity on a BIAB porter by accident.
Really great article, and an excellent way for beginning brewers to venture into new and different ways to brew.
I do think, however, that it should be noted that there is a risk involved with double crushing and longer mashes. Double crushed grains have a very large potential to break the husks, which can add off-flavors and will contribute to haze. Also, you don't want your crushed grain to be too fine (too floury). This will decrease viscosity, and cause a stuck sparge. In addition to that, increasing the mash time beyond 75 minutes can also begin to leach polyphenols from the husks, again causing off-flavors (there is indeed a down-side to mashing for too long).
As mentioned earlier, it's well worth the time to look into pH treatment. Having the correct mash pH will aid in the activation of enzymes to breakdown the starches in the grain. A single crush should be more than sufficient, along with a 60 minute mash (not including the additional 10 minutes at 170* F for protein rest).
For small batches I add my grains to the heated water and steep/mash. Pour wort thu a kitchen type strainer into brew pot. Dump the grains back into 1st pot, add water to rinse and pour through strainer again.
Done. No fuss, no muss with bags.