Does BIAB lead to more unwanted malt residue entering the boiler and does this affect final beer quality

Question

Does BIAB lead to more unwanted malt residue entering the boiler as there is no recirculating of wort until it runs bright, prior to boiling, as during a traditional sparge, and does this affect final beer quality

Answer 1

TL;DR There might be difference in final beer quality, but:

1. The difference will be SMALL (and who knows, BIAB might actually give you a better result).
2. You can mitigate any negative effects with other aspects of your process.
3. There are other parts of your process that have MUCH more impact on your beer than the choice of how you lauter - focus on these first to have more positive impact on your beer quality.

In theory, the mesh size of the bag is actually finer than the filtration achieved in a traditional mash bed. This means that the BIAB wort will have smaller particles than a traditional lauter.

I own (and am the brewer for) a licensed nano brewery. My brew house consists of a 50 gallon kettle, a very large bag, and an electric winch to lift the bag from the kettle at the end of the mash. I mash uninsulated, but only lose about 1.5F per hour during the mash (good volume to surface area ratio in the bigger kettle).

Due to the size of the grain bag, I am definitely in the "no-squeeze" BIAB camp (at the very least due to practicality). Due to the limited kettle size for my desired batch size (7/6 of a barrel), I always am short on wort volume, so I "sparge" with a few gallons of hot water from a hose into the top of the bag while it drains. I also use Visco-Buster in every mash to improve the speed at which the bag drains (this is a White Labs product - no affiliation, other than as a customer).

There are never ANY grain particles floating around in the wort. However, all of the soluble stuff is still in there (proteins, etc.). Lots of trub - as much or more than a traditional lauter. Perhaps additional trub is a result of the much finer crush I can use on the grains?

I always use Irish Moss during the boil and gelatin when cold crashing, and my beers always come out crystal clear.

There are so many brewing process options available that it is impossible to say that one lautering technique or another is going to make or break the quality of the beer. I think you need to pick the equipment and process that works for you and your budget and brewing time that is available. Once you have picked your equipment and general approach, you will want to optimize the rest of the process.

For example (and I don't know if this is true or not in general), let's say that BIAB tends to result in hazier final beer. Ok, that just means that it is a little more important to use fining agents in the process than it would be with a traditional mash. I am good with that, as I would probably be fining no matter what (just to be sure the beer is clear, if it is appropriate for the style).

In my experience, the details of how you produce wort is far down the list of importance when it comes to the quality of the final product. Off the top of my head, in order of importance:

1. Freshness/quality of ingredients.
2. Pitch proper amount of happy yeast.
3. Oxygenate wort at the start of fermentation.
4. Pay strict attention to cleanliness on the cold-side. Avoid infection.
5. Proper fermentation temperature control (and temperature schedule).
6. Recipe.
7. If mashing, proper pH (much less of an issue for extract).
8. If mashing, proper strike water temperature (to hit desired mash temp).
9. Adjust your water profile to support the desired style (get a water report from Ward Labs - no affiliation, other than being a happy customer).
10. Strong rolling boil, fast cooling of wort at the end of boil.
11. Limit oxygen exposure at all times after fermentation begins.
12. All grain rather than using malt extract to produce base wort.
13. Fining.

Yes, I really think all grain vs. extract is that far down the list. And this question is about a nuance of the lautering process, which is just one step in the mashing process. Breweries use grain because it is MUCH less expensive than extract (last time I calculated it, extract is 4x the cost of the equivalent base malt). This difference is critical to the brewery, but relatively small at the homebrew scale. I will also note that breweries will routinely use some malt extract to hit a higher OG than their mashing equipment can reach.

Bottom line: The choice between BIAB and traditional lauter is a minor detail. Pick one and create/optimize your process around that. Or, stick with extract (plus specialty grains) for now and focus your time and effort on all the other stuff that has a bigger impact on the final product.

If you have a limited budget (and you have your heart set on all grain), definitely go BIAB and put your time and money into figuring out yeast management (storage, starter, etc.), fermentation temperature control, and oxygenation. Happy yeast makes good beer. Proper water chemistry can turn a good beer into a great beer, and water tests and brewing salts are inexpensive (and you should definitely tune the water chemistry for each recipe to match/support the style).

Regarding the specific comparison of mashing style, this is an interesting read.

I will note, though, that I am pretty sure that a stuck sparge is impossible to achieve with BIAB. I can attest to the peace of mind of never having to worry about a stuck sparge, which will definitely ruin your day when it happens.