BIAB with 2 bags?

[raysmithtx]

Just thinking out loud here. I EBIAB and use a Wilser bag and am thinking about using 2 bags. One for the mash and one for the boil. I would put both bags in the kettle at the beginning, add the grain and after the mash remove just the top bag. Then I proceed to the boil, adding hops, etc. and at the end of the boil I would remove the second bag.

I'm thinking this would keep a lot of trub and sediment out of the fermentor,

Anyone ever tried this? Any feedback on this idea?

 

[brew703]

Is the second bag just for hops? If so, use a hop sock or something.

 

[ancientmariner52]

I like the way you are thinking here.

A couple of considerations, though. When you lift the inner bag, won't they outer bag be likely to cling to it? Secondly, what keeps the outer bag from floating around during the boil? You could perhaps weight it somehow, at the risk of interfering with natural circulation. This might create a steam bubble, with unpredictable, possibly disastrous results.

The above is speculation, I don't do BIAB. I have a history with boilers and reactors though.

 

[nh_homebrew]

Interesting. I wondered about using two bags but just to make it easier to lift and sparge. Moved away from BIAB recently though

 

[applescrap]

Sounds like a decent plan and ancientmariner gives you a couple good considerations. I get a lot of sentiment too and while imo it doesnt matter it makes the 6.5g bucket difficult to get 5.5g of beer out of with near 1g of trub. I have been too cheap to do it but I want the 8 gallon fermenters so I can have plenty of headspace. It would be nice too get more volume. Other than that why do you want to keep the sediment out of the fermenter?

 

[jalc6927]

I think if the trub was fine enough to go through first bag it would Also go through second?

 

[ancientmariner52]

I think if the trub was fine enough to go through first bag it would Also go through second?

I believe what we are looking at is: inner bag = mash lauter tun, outer bag = hop spider + trub filter? So, no trub until first bag with spent grain is removed.

 

[jalc6927]

Yes, the trub will still end up in kettle though because it’s too fine for bag to catch or it would all be caught in first bag

Use a hops sock or spider to limit that, but that’s after the bag is removed anyway

 

[ancientmariner52]

Maybe it's a matter of definitions. As I understand it, trub is 'generated' during the boil, from coagulation of proteins and from hop debris. So trub, by that definition can't be caught by the first bag because it hasn't formed yet. Does that make sense?

I agree, the boil bag will not catch it all. That's why I whirlpool and settle before pumping to the cfc and fermenter.

I would suggest a test run with just water and a bag. If my first two concerns are correct, this is not going to work for other reasons.

 

[raysmithtx]

Sounds like a decent plan and ancientmariner gives you a couple good considerations. I get a lot of sentiment too and while imo it doesnt matter it makes the 6.5g bucket difficult to get 5.5g of beer out of with near 1g of trub. I have been too cheap to do it but I want the 8 gallon fermenters so I can have plenty of headspace. It would be nice too get more volume. Other than that why do you want to keep the sediment out of the fermenter?

I use closed fermentation and ferment in a corny keg using a spunding valve. I connect two cornies while fermenting so I have less chance of O2 with my beer when transferring to the serving keg. The cornies have reduced the amount of beer I can ferment to slightly less than 5 gallons. My thinking is that less trub in the fermenter leaves more room for beer.

 

[jalc6927]

Or you can brew another half gallon or so to get you 5

 

[raysmithtx]

Since i ferment in corny kegs I can't just brew another half gallon because the wort is already to the top weld.

 

[Partagas]

I dont like the idea of boiling with a bag, what if that bag sticks to the sides or bottom of the kettle and scorch? Use a hop sock or spider, cause its really the hop sediment that may affect your final product. Beer trub is not as evil as they make it out to be. Like someone said its the product of boiling and proteins in the wort.

 

[raysmithtx]

I dont like the idea of boiling with a bag, what if that bag sticks to the sides or bottom of the kettle and scorch? Use a hop sock or spider, cause its really the hop sediment that may affect your final product. Beer trub is not as evil as they make it out to be. Like someone said its the product of boiling and proteins in the wort.

Since I EBIAB there is no fear of scorching the bag. I use an ultra low wattage element and have had the existing bag resting on the element for over 100 brew sessions with no problems at all. I'm not a fan of a hop sock/spider because they tend to restrict the flow of wort around the hops. A really large hop sock is basically what I'm talking about here. Any additional trub it catches, so much the better.

 

[Partagas]

Just thinking out loud here. I EBIAB and use a Wilser bag and am thinking about using 2 bags. One for the mash and one for the boil. I would put both bags in the kettle at the beginning, add the grain and after the mash remove just the top bag. Then I proceed to the boil, adding hops, etc. and at the end of the boil I would remove the second bag.

I'm thinking this would keep a lot of trub and sediment out of the fermentor,

Anyone ever tried this? Any feedback on this idea?

Any updates on this? Has the second bag made a difference in the amount of trub left?

 

[raysmithtx]

Still haven't had a chance to try it. Life got in the way and I haven't even had a chance to brew much. Still on my 'things to try' list though.

 

[TwistedGray]

Just do what I do; it's easier and you don't run the risk of scorching the bag due to the open flame.

Use the BIAB bag as normal, dump grain, rinse bag, set aside. Run through your boil, add hops as needed, cool wort, and run all wort through the bag when dumping into your fermentation vessel. That will catch most of the trub and aid in aerating the wort.

I've done this a few times now after self-complaining of the same issue. It works pretty well.

 

[applescrap]

That sounds like a good plan, some sort of secondary filter after boil. I don't know how that will work with the low oxygen. As a side note I use 2 bags when mashing because I don't have a wench and it's easier to manage two sacks instead of one big one.

Some considerations are to do some sort of whirlpool and let the gunks settle and don't transfer it to your corny keg. I am not sure if that will help with your end trub level but I think it would. Brew a pinch more as recommended and transfer as much beer as you can leaving the solids behind. Ultimately if I'm correct biab is known for higher trub levels and might not be the best method for what you need. As I stated before I produce such a massive amount of trub, sometimes well over a gallon that an 8 gallon fermenter makes better sense because it's too hard to manage five and a half gallons beer and 1 g trub in a 6 1/2 fermenter. Maybe a simple batch sparge with good filtering could help. Bag in cooler?

 

[Mothman]

I've also done as Twisted suggests.

I use a bucket for primary, and I've lined the bucket with the grain bag, dumped the (cooled) wort into it, then pulled out the bag and let it drain. It's seemed to work fairly well, other than I've found it a minor hassle to drain that bag, as the hop debris, trub, etc, tends to really clog up the mesh... so it's involved lots of repositioning the bag to a "fresh" area, squeezing, etc.