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BIAB All-Grain Brewing


Like most brewers I started to brew with extract – It’s easier as it leaves out the (seemingly) complex task of mashing. It also saves a lot of space and money since mashing requires more vessels than just boiling extract and hops. However, after a while you realize that using extract doesn’t give you a lot of options so most people start to steep grains to add variety to the beers they brew. This is just a step away from a method of all-grain brewing that I use to make beer, brew in a bag or Biab for short. Biab originated in Australia and I understand it’s a very popular way to brew over there and no wonder : it’s easier to set up, basically you only add a bag that can hold all your grain to your steeping set-up. Here are some pictures and explanations of the different stages of brewing with this method.

Heating the strike water:

I start of a brew by measuring out the mash water (typically 20 litres / ~5,2 gallons) to my boiling kettle. I use the electric stove in my flat, if you have the option to brew outside, a gas burner is a much quicker way to heat your kettle. The target temperature of the strike water varies between 64-71 celsius (147-159 F) as you want to heat the water a few centigrade above your target mashing temperature (the temperature falls when you add the malt, after a few brews you get the “feel” on how your particular set-up works). If you’re adding any salts to the mash it’s best to add them at this stage, gypsum especially takes some time to dissolve. While the water heats I start to work on the malt.


The colander in the bottom keeps the bag from melting during mash-out.

Weigh and crush the malt:

I weigh out the malt on my kitchen scale and use my malt-mill (hand-operated) to crush it. With the biab method you can set the mill to a slightly tighter setting than with a traditional mash since you aren’t sparging where a too fine crush could cause problems. This helps to compensate for the slightly lower efficiency of the biab mash. Don’t go overboard though as you don’t want to crush the husks which could lead to a tannin off-taste.

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Add in the malt:

Usually by the time I’m done measuring and crushing the malt the strike water is close to the target temperature. I insert the bag in to the water (I use a commercial bag widely available, some people make the bag themself or use a paint strainer) and slowly add the malt while mixing at the same time. The goal at this stage is to prevent clumps of malt from forming and to mix the mash evenly so that there are no heat-pockets, you want the mash to be as uniform as possible. I keep a thermometer at hand at this stage and correct the temperature after adding the malt if necessary. It’s always easier to add cool water to get the temperature down than to heat the mash back up so keep that in mind. I don’t usually measure out the pH of the mash: I rely on the water salts I add to keep my pH in a suitable range and add some acidulated malt to very pale mashes. The water over here is very neutral with minimal mineral content (according to the municipal water report) and I have not had any problems with my water thus far.



I use fleece blankets to insulate the kettle while mashing. Very little insulation is needed since the stove keeps some heat under the kettle even after it’s turned off and large amounts of liquid are surprisingly slow to cool. I usually mix the mash in intervals of 15 minutes or so to make sure there are now clumps and to keep the temperature evenly distributed in the kettle. After an hour (typically) I remove the blankets, turn up the heat and raise the temperature to mash-out (75C/168F). After this I lift the bag out of the wort and hold it above the kettle to drain for a bit. I then put it in to a bucket with an upturned bowl in the bottom to let it drain. At this time I measure the pre-boil gravity of the wort and add some water if I’m over the target (usually) or boil a bit longer if under. All the while the wort is heating up and I use the time it takes to measure out the hops.



Make sure you have proper ventilation where you boil the wort. This is especially important indoors, I have a powered ventilator and open my kitchen window and balcony door to create a strong draught. It’s also a good idea to use 2 burners to start of the boil and then find a setting where you get a strong boil going without the risk of an over boil. Also, do not keep the lid on during the boil as this can lead to DMS problems in the beer. Never leave a boiling kettle un-guarded and be carefull when adding hops as that can lead to an over boil as the hops serve as nucleation sites.  I tend to hover around the kettle in order to skim the surface of the beer while boiling as this servers to minimize the trub in the resulting wort. I have the hops, kettle finings, yeast nutrient etc. measured out in to cardboard cups with the boil-time penciled out in the cup. This prevents me getting confused with the additions, a lesson learned in one of my earliest brews. A typical boil-time is 60 minutes to 90 minutes. 90 minutes is usually used with a mash containing pilsner malt, as a longer boil reduces the risk of DMS (Dimethyl Sulfide) off-taste. This isn’t something I’ve actually experienced myself but supposedly DMS gives a cooked corn-like taste to the beer and this compound is more common in lighter kilned malt and is driven off by boiling, hence the 90 minute boil with pilsner malt.

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I use an immersion chiller to cool my wort. I put it into the kettle 10 minutes before the end of the boil to sanitize it and then after the boil (and usually a hop-stand) move the kettle with the chiller to my kitchen sink that has cool water in it. I circulate the cool tap-water through the chiller and the outlet is in the sink so that the water passes both through the chiller and the outside of the kettle for maximum effect, then drains in the sink beside the one I’m cooling in. I keep a thermometer available at this point as well (added to the hot wort to sanitize) and mix the wort regularly with a large paddle (also added to the near boiling wort in time to sanitize). After the wort is cooled to a temperature slightly under the ambient temperature I measure its original gravity. After that I put a sanitized biab bag over the chiller and rack the wort in to the fermenting vessel from within the chiller. This keeps the hops and the trub in the kettle. Currently I use better bottles for fermenting as I find them to be both safer and easier to handle than either glass or large buckets. Everything that touches the wort at this point is sanitized with either heat or star san, a very usefull no-rinse sanitazer.

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Aerate the wort and pitch the yeast:

I simply shake the better bottle vigorously for two minutes to aerate. For big beers, some oxygen would help with the initial growth of the yeast but oxygen cans aren’t available to households over here. I haven’t found this to be a problem since I rarely brew really big beers (gravity over 1.080) and if I do, I can use twice the usual amount of dry yeast to get a high cell count, or make a larger starter. I use re-hydrated dry east for most beers that don’t require a special yeast character and this has worked well for me thus far. If I end up using liquid yeast I have learned that it is best to make a starter to make sure you have a healthy dose of yeast to pitch. In the past I have also pitched the slurry of completed fermentations, racked over a yeast cake, used washed yeast and none of these have caused any problems. It’s very important to take care of sanitation with any of these methods (as with anything on the cold side of brewing) so keep some star san in a spray-bottle near at hand.


As of yet I’m at the mercy of ambient temperatures which I plan to correct by getting a fermenting fridge before next summer. I try use a yeast that thrives in the temperature present during fermentation so it’s mainly saisons during the summer and other ales during the fall/winter. Lager will have to wait for the fridge. Nothing much else to it, I either use a blow-off tube if there is a lot of wort, or else use sanitized aluminum foil over the mouth of the bottle at the start of the fermentation and then a basic air-lock when the activity turns down. At this point your work is done and you just wait for the yeast to do its magic of turning that wort in to beer.


I’m adding some more pictures to this guide later after another brew and will try to format it to make things clearer when I find that my English or brewing skills have left something unclear. If you have any questions please leave a comment. Hope this helps anyone wanting to brew in a bag!

Sources :

Beersmith article on BIAB

BIABrewer Forum


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