BIAB basics question

[kmmuellr]

I've been an AG brewer since around '97 or so. recirculated, 3 tier, fly sparge, gas fired, standard system. I'm in the process of building a eBIAB system and have never even witnessed a BIAB brew.

I know that the general BIAB process is to do a full volume mash, then pull your bag. Is there any advantage of doing a thicker mash, and then adding the water needed to go full volume and then pull your bag? I suppose kind of like a batch sparge?

Whats the advantage and disadvantage of having more water volume in the pot during the mash?

Thanks!
Kevin

 

[Bellybuster]

a quazi sparge may or may not get you a few more points from the mash but full volume mash is just so easy when it comes to calculating recipes and efficiencies.

The only time I ever do a sparge is when I want more volume than my pot can handle. I pull my grains then top off the kettle by pouring the extra water through the grains. I don't even heat this water addition. I do get a bit more sugar from the grain but really not very much

 

[Bellybuster]

just for interest, I too came from the 3 vessel world and will never go back. BIAB is just so easy and brought the fun back into brewing for me.

 

[Gavin C]

Whats the advantage and disadvantage of having more water volume in the pot during the mash?

Thanks!
Kevin

There really are 3 advantages to having more water in the pot for a full volume mash.

• A thinner mash will result in higher mash efficiency all else being equal.
• A thinner mash will of course be greater in volume, this larger thermal mass will result in better mash-temperature stability
• A thinner mash and a no-sparge process means that the wort lost to grain absorption contains less sugar than a thicker mash would. (Obviously a thicker mash will usually be followed up by a sparge to offset this)

 

[doug293cz]

You are better off with a thinner mash (higher water/grain ratio), as thinner mashes have faster starch to sugar conversion rates. Since most brewers with low efficiency issues are actually experiencing incomplete conversion within their alloted mash time, having a faster conversion rate will lead to more complete conversion and improved mash efficiency (ref: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Mash_thickness.)

Here's a handy chart that shows how lauter efficiency varies with grain absorption for both full volume (no sparge) and equal runnings batch sparge. Mash efficiency is lauter efficiency times conversion efficiency (percent of starch converted to sugar.) Grain absorption is controlled by how well you drain/squeeze your bag. Chart assumes 6.7 gal pre-boil volume for a 5.5 gal post-boil volume.



And another chart that shows the pot size needed for a five gal (6.7 gal pre-boil) batch with various grain bill weights. Assumes 0.08 gal/lb grain absorption.



Brew on

 

[kmmuellr]

Great answers! Thanks!

Kevin

 

[Bigarcherynut]

Don't mean to high jack but need some help understanding things.

I'm in the process of building an E-kettle. I've been reading a lot of BIAB and now that I'm going all grain have been reading about sparge techniques. My kettle is 20 gallons so it appears doing 5 gallon batches I can do full volume. Can someone explain to me how the water volume is calculated. Am I correct thinking that I have a 20 gallon kettle this will work for full volume.

Thanks

 

[pricelessbrewing]

Oh jeez yes, I've done full volume in a 9 gallon kettles for typical brews.

@ Kevin, Greetings! I used to live in plymouth until about 3 months ago. Small world. Are you a member of ford or solhbc?

 

[RM-MN]

Don't mean to high jack but need some help understanding things.

I'm in the process of building an E-kettle. I've been reading a lot of BIAB and now that I'm going all grain have been reading about sparge techniques. My kettle is 20 gallons so it appears doing 5 gallon batches I can do full volume. Can someone explain to me how the water volume is calculated. Am I correct thinking that I have a 20 gallon kettle this will work for full volume.

Thanks

Start by deciding what final volume you want to go into the fermenter. (I might like 5.25 gallons, you might like something different) Add to that the amount of boil off you expect, maybe a gallon, maybe 2, maybe something else depending on your kettle and how long and hard you boil. Add the amount of water that will remain in the grains. That amount will depend on whether you squeeze like it owes you money or if you just let it drip for a minute. From all that you can calculate that there isn't a real calculation that you can do. I'd suggest you not worry too much about it, plan for your typical boil off and if you don't boil off that much that day, you get more beer. If you boil off too much, you can have less beer or just add water back since that is what you boiled off to start with.

I've managed a full volume batch in a 7 1/2 gallon pot so I suspect you can do one in your 20 gallon pot very easily. Unless you have a really big grain bill, your 20 gallon pot would be fine for a 10 gallon batch too.

 

[Gavin C]

Don't mean to high jack but need some help understanding things.

I'm in the process of building an E-kettle. I've been reading a lot of BIAB and now that I'm going all grain have been reading about sparge techniques. My kettle is 20 gallons so it appears doing 5 gallon batches I can do full volume. Can someone explain to me how the water volume is calculated. Am I correct thinking that I have a 20 gallon kettle this will work for full volume.

Thanks

You need to work backwards in brewing to calculate how much water you need.

Single vessel, full volume, no sparge brewing is very easy to calculate but you do need to know some values unique to your setup.

Below is an example of volumes for an averaged brew for a ~1.050 OG beer and a 10 lb grain bill . I use an 11 gallon pot. Below are approximate values

7.5 gallons of strike water

-0.5 gallons of wort loss to grain absorption (0.05 gallons/pound of grain not accounting for thermal expansion of wort)

=7.0 gallons preboil volume

- 1.0 gallons per hour boil-off rate (lets assume a 60 minute boil)

-0.25 gallons of wort lost to chiller/hoses/hop absorption/kettle trub

-0.25 gallons of shrinkage (4% volume reduction from boiling to ~70F)

=5.5 gallons in the fermentor (your chosen batch size)

-0.5 gallons lost to fermentor trub

= Full 5.0 gallon keg of tasty beer

 

[kmmuellr]

Oh jeez yes, I've done full volume in a 9 gallon kettles for typical brews.

@ Kevin, Greetings! I used to live in plymouth until about 3 months ago. Small world. Are you a member of ford or solhbc?

F.O.R.D member since Like 98 or so.

Haven't been to any solhbc meetings and only a few aabg.

Kevin

 

[pricelessbrewing]

Cool. I never ended up at the ford meetings but I joined the fb group.

 

[tennesseean_87]

I came in the forum to ask the same question.

Is there any difference in the finished product with an extremely thin mash? I had envisioned heating full volume of strike water, draining out until I had a standard thickness (1.25 or 15. qts/lb), mashing for 60 minutes, adding back the rest of the water and stirring for a 'sparge' while beginning to heat to mashout then boil temps, then pulling the bag and squeezing.

 

[applescrap]

Thank you gentlemen for your wisdom. Does it really matter whether you go thick and sparge or full volume and squeeze or dance with your kettle in the moonlight.....yes! Some ways are easier then others. I'm starting to think doing brew in a bag in a cooler is the way to go. You don't have to pull the bag I know it's another thing to clean but you don't have to pull the bag or winch it or do anything just drain and throw away grains Plus insulation is killer

 

[doug293cz]

I came in the forum to ask the same question.

Is there any difference in the finished product with an extremely thin mash? I had envisioned heating full volume of strike water, draining out until I had a standard thickness (1.25 or 15. qts/lb), mashing for 60 minutes, adding back the rest of the water and stirring for a 'sparge' while beginning to heat to mashout then boil temps, then pulling the bag and squeezing.

There is no benefit to what you are proposing. Adding water at the end of the mash is nothing like an actual sparge. You are likely to get lower efficiency (due to slower starch conversion) with the thicker mash. Adding the extra water prior to any draining has 0 lauter efficiency benefit vs. a full volume mash. Sparging (adding fresh water after draining) rinses additional sugar from th grain mass, and improves lauter efficiency. If you want an efficiency boost, drain first, then add the extra water for a proper sparge.

Kai Troester did not find any difference in wort attenuation for different mash thicknesses (ref: http://braukaiser.com/wiki/index.ph...ncy_in_single_infusion_mashing#Mash_thickness.)

Brew on

 

[kmmuellr]

I did my first BIAB in my gas system while still working on my electric system.

Awesome time saver. Great efficiency, etc. once set up on my ebiab system, I'll dial in my process. Suffice to say, I'm sold!

Kevin

 

[pricelessbrewing]

Sounds great. Just got back in town yesterday for the holidays.

 

[tennesseean_87]

There is no benefit to what you are proposing. Adding water at the end of the mash is nothing like an actual sparge. You are likely to get lower efficiency (due to slower starch conversion) with the thicker mash. Adding the extra water prior to any draining has 0 lauter efficiency benefit vs. a full volume mash. Sparging (adding fresh water after draining) rinses additional sugar from th grain mass, and improves lauter efficiency. If you want an efficiency boost, drain first, then add the extra water for a proper sparge.

Kai Troester did not find any difference in wort attenuation for different mash thicknesses (ref: http://braukaiser.com/wiki/index.ph...ncy_in_single_infusion_mashing#Mash_thickness.)

Brew on

I must have mis-remembered that bit about attenuation. Maybe I was also thinking about avoiding the 90-minute mash the Aussies recommend, but apparently isn't necessary. Either way, it seems I can keep things simple!