I have read about the brew in bag method of homebrewing, pioneered by the Australians, over the last few years, but had never actually seen it in practice before. A week or so ago my friends and fellow JABbers, Matt and Anna brought over their set-up to my place and showed me how it was done, while I simultaneously brewed an all-grain batch in my three-tiered system. The idea of BIB is to skip the steps requiring an extra vessel for mashing in and possibly even for sparging.
It was very interesting to see the BIB in action and parts of the process were quicker, others longer. I'll do a quick run-down here, but keep in mind that I was just watching this, not taking part. They were using an all-grain kit from Midwest for a 1.052 OG beer.
The first step was setting up the brew pot (they had a 8 gallon, but plan to get a bigger pot in the future.) Getting water up the proper mash temp is the next step. Ideally one would have this plugged into a program like Beersmith to do all the calculations before-hand. Based on your vessel, vessel temp and grain amount you should be able to calculate the goal water temp a few degrees above the desired mash temp, so upon adding the grain your temp hits right around your goal. Getting this aspect consistent requires taking good notes and repetition before you can feel comfortable with your system. Once you have reached your desired water temp, you add a large nylon bag to line the inside of the pot and then add the grain inside it. With the top of the bag open, you can stir the grain as it absorbs the water and is turned into your mash. Using a brewer's thermometer insert this into the middle of the mash and see if your temp is right. If you need to make adjustments, you can do it now. If too hot, keep the lid off and stir some more to cool it down (or add a bit of cool water if needed.) If too cold, you can add a bit of hotter water or even direct fire the pot for a short time to get it up to temp. Once it is all of an equal consistency with no clumps or dough balls, you can tie up the top of the bag, or leave it open to give better access for stirring and temperature taking. Put the lid on and let it sit for your usual mash time (about an hour typically) checking temps occasionally to make sure you haven't dropped too much. So far pretty much like every all-grain mash, just inside a bag.
Once an hour had passed, Matt demonstrated a technique he uses that simulates a batch-sparge. He has some water heated up to about 170 in a separate pot sitting by. He picks up the bag full of grain, letting it drain back into the pot, but not squishing it to avoid extracting too many astringent tannins. The bag full of grain then goes into the pot of warm water to rinse the grain and also to raise the temp, like a mash-out step to inactivate the enzymes. This stage is about 15 minutes long. He then moves the bag to an empty smaller pot and lets it sit there a bit. The "sparge" liquid is then added to the boil pot where most of the first wort is already on the flame and working toward the boil. After a bit of time the grain bag is emptied/discarded, and the residual drainage wort collected in the empty pot is added to the boil as well. Waste not want not!
The boil is pretty much the same as any homebrew batch from here on out. With Matt and Anna's smaller pot it is difficult to do a full 5-6 gallon boil without massive boil-overs, so they have to add back some water to the carboy/fermentation bucket after the wort is chilled.
While watching this I was impressed by how easy it was. One could potentially skip the "sparge" step and just end up with a first wort if you lacked a second large pot and save space and time, at the expense of efficiency. They were done before my traditional brew was over, mainly because of the 45 minute sparge I was doing. I believe their efficiency has been around 70, which is traditionally where most homebrew recipes are set as a baseline. Supposedly BIB should be around 60%. I'm guessing that the extra sparge step and the drained off final wort step have increased Matt and Anna's efficiency from classic one-container BIB. Whatever your efficiency ends up as, if you can take notes and find out your usual number, you can increase your base grain amount in the future to get your OG levels to where you want it. Overall this is a great way to do all-grain brewing without investing in a lot of extra equipment--make sure you really want to take the plunge. I've seen several people over the years who either tried to start with a huge all-grain set-up or advanced to that method and then decided it was too much work or time.
Keep in mind this is a surface-level review from someone who hasn't actually done this hands-on, so I might have missed a few details. Have any of you used this method and if so do you have advice for folks doing this? If so please comment here and let us know!