The benefits of electrical brew-in-a-bag systems

March 05, 2015 4 min read 2 Comments

Retro BIAB - where it all started.  

Brew-in-a-bag systems have been catching on like crazy over the past five years. And it’s no wonder. BIAB is a great option for any home brewer – both new brewers and veterans alike. Whether you’re ready to take the step up from brewing from extracts or you’re looking to downsize and simplify your brewing system, there are a lot of advantages to going the BIAB route.

I used to brew with a traditional three-vessel brewery – I invested a lot of time and money into my system, in fact. But after all that, I’ve realized that the BIAB method is preferable. You can get exactly the same flavour profile from a BIAB system as you can from the most expensive professional brewing systems on the market. BIAB systems are smaller and easier to set up. Less equipment means less expense. They take up less space and some don’t even require modifications to your household electrical systems. And as long as you’re using a bag made of nylon – which is inert and non-leaching – you don’t need to worry about steeping it in the hot wort.

But for me, the biggest advantage of BIAB is the time-savings. Where a brew day can take eight or nine hours with a three-vessel set-up, you can have your BIAB brew done and in the fermenter in under four.

There is a widely held belief that the trade-off to all of these advantages is reduced efficiency. With a three-vessel brewery – where you’re fully rinsing your grains for maximum sugar conversion – you're able to reach an efficiency of up to 90%. With the traditional brew-in-a-bag method you're only going to achieve about 65%. But, I’ll present you with a few tips to get your efficiency up to at least 80%. Meaning you only need to make up a 10% grain loss by buying a little extra base malt. Using the techniques outlined below, I’ve been able to get as high as 89% mash efficiency!

  1. You’ll achieve your biggest gain in efficiency by starting with a super fine crush. I ask my local home brew shop to double-crush my grains. Some people believe that by crushing the malt too fine you will end up with excess tannins in the beer. But tannin extraction happens during a slow mash – because BIAB is a faster process, this just isn’t going to happen. 
  2. Your second biggest gain in efficiency will come from mashing for 90 minutes instead of 60. This will ensure full conversion of your sugars. 
  3. For a few extra gravity points try this: heat up a large pot of water on the stove to mash-out temperature and then rinse your grains after you’ve removed them. Put the grains into your primary bucket or a pot that can hold the grains in the basket. Then rinse the grains with water at the ideal mash-out temperature of 168 degrees Fahrenheit. Collect your rinse water and pour that over and into the boil. This will help you get maximum volume out of your small brew system.  This method also has the benefit of increasing your efficiency by up to 10%. Don’t forget to subtract your mash addition from your initial strike volume! 
  4. Finally, find a way to squeeze or press your grain bag before discarding your grain. I usually leave my grain bag in the mash basket, prop the basket over a pot and squeeze it with a large spoon. Collecting even a little more wort in this way is going increase your efficiency. Whatever you manage to squeeze out of your grain at the end is denser and more concentrated so it’s definitely worth the effort. 

Aside from the concerns over reduced efficiency, the only downside to BIAB is that it can be a bit of a messy process. But this is easily remedied if you take the time to properly prepare before starting your brew. First of all, make sure you’re using a system that uses a basket or a mash screen over the element. You don’t want to risk melting through your bag.

And secondly, make sure you’re prepared to deal with that hot grain bag when it’s time to remove it. If you’re brewing a bigger batch, you’ll be dealing with a scalding hot bag filled with saturated grains that could weigh upwards of 25 pounds. You might want to consider installing a hoist if you don’t have the strength to lift the bag out safely without spilling your wort. Make sure to have a five gallon bucket right close at hand, or set up your brewer right beside the sink and dump your bag in there to let it cool. Be careful – the hot grains can scorch you.

I hope you’ve found some useful BIAB tips in this week’s post. If you’re considering getting into BIAB brewing, check out our shop  for our 3-gallon brew system as well as our standard 240V breweries.  And feel free to get in touch  if you have any questions.

2 Responses

Ronald Morrison
Ronald Morrison

May 01, 2015

I’m “that guy” that tried the shorter mash times and while conversion happens very quickly with a fine milled grain, flavor extraction seems to take a bit longer. I’ll probably stick with a 20 minute mash for that reason. If my grains were crushed at the LHBS, I wouldn’t go less than 30 because their crush isn’t likely to be as fine as the milling I do with my Corona mill.

Tannin extraction is driven by the mash pH. If you keep the pH below about a 6.0 pH you won’t extract tannins. Even with the higher pH you need temperature above mash temps to extract a significant amount of tannins.

My first batch I did BIAB with no sparge and a 60 minute mash and achieved 80% efficiency. By reducing the water during the mash just a little and using that water for sparging just by pouring it through the grain that efficiency went to 85%. If you are only getting 65% efficeincy you need to get the grains milled finer.

Your sparge water doesn’t need to be at mash out temperature, even cold water will extract nearly the same amount of sugars since the grain will be hot and wet and will heat up the water anyway. Using cold water will also cool the wet grains making it easier to squeeze the bag.

Squeezing the bag is optional as just letting it hang will allow almost as much water to drain out. Squeezing will speed up the process though. It will take nearly 20 minutes for the wort to drain and squeezing will get a little more wort in less than 5 minutes. If you do a good squeeze, the bag will not drip when you go to discard the grains.

Benson Ledbetter
Benson Ledbetter

April 29, 2015

Quick comment on point #2 above. Many of us who BIAB are finding that the very fine crush allows us to get full conversion with a mash of 30 minutes or less. 30 minutes has actually become my standard mash time. A fellow brewer even attempted to lower his attenuation by reducing his mash to 20, 10 and 5 minutes with three different batches. Surprisingly even at 5 minutes he had full conversion and hit his OG.

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