BIAB efficiency without sparging

[GuyBob]

Third BIAB session today. Went fairly well. I am not quite hitting my target OG's though. I've noticed over the past three I am short about .004 or so off. I am doing true full Volume BIAB. Starting off with about 8-9 gallons depending on grain bill. I am also adding about a 1lbs to my recipes to make sure I've got little more sugar. Still off. Today I measured my pre-boil SG and it came in at 1.058 with a OG going in fermenter at 1.070 which was about 5.5 gallons after 60 mins boil. Target OG was 1.074. I had 13.5 lbs of pale malt 2 row. I also whirlpool with a immersion chiller in a 16 Gallon kettle. Mash was 152-155 for 75 mins and mashed out at 170 for 10 mins. I also did squeeze the bag while hanging over kettle. Long winded but what heck am i doing wrong. Sparge? Thanks for any one throwing out their thoughts.




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[rlonardo]

Sounds like your efficiency is different from your recipes. Either bump up the amount of grain to make up for the lower efficiency or do something to bump it up (finer crush, sparge, etc.)


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[LLBeanJ]

What efficiency are you using to arrive at your targets? I found that 78-80% was what I typically got with no-sparge BIAB.

 

[GuyBob]

I have been using this calculator but it doesn't have efficiency. I build my recipes on Beer-smith which my equipment is set at 70%. So using a combination I guess. I also mill my grains twice.

http://biabcalculator.com


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[Watzee]

You could try crushing your grains twice or set you crusher for a finer crush. I do a makeshift sparge and squeeze my bag.

For a sparge I will use 3 food safe 5 gallon buckets from home depot (4-5 bucks each) I drilled holes in the bottom of one. Put your bag in the one with holes... pour water over top and then just keep switching buckets and poor your wort into the kettle as you are bringing it to a boil.

 

[ram5ey]

That is a pretty big boil off rate going from 1.058 to 1.070, but that's another matter. I found crush to be the biggest thing...Do you crush your own? Also have you tested for conversion? Some people that biab do 90min mashes to get full conversion in the thin mash....

 

[GuyBob]

Watsee. Are you draining out the preboil wort over top of the grains? I crush my own at a home brew shop. I run them through twice. I am not sure of the gap. With that much grain I should be hitting the OG every time.


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[GuyBob]

Watsee. Are you draining out the preboil wort over top of the grains? I crush my own at a home brew shop. I run them through twice. I am not sure of the gap. With that much grain I should be hitting the OG every time.


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[newnick]

I was having a similar problem and cut back on the water about .5 gal at the start. I also leave about .5 gal out in the beginning and use it to rinse the grain bag over the pot. I've been getting much better numbers now.

 

[Watzee]

Guy bob

I just use fresh warm water over top the grains. I sparge until I get the right amount of wort in my kettle.

 

[1MadScientist]

Could it be the bag? It should be big enough that your kettle fits inside it.

 

[GuyBob]

The bag is custom and is plenty big enough. I'm wondering if I'm going off a 5 gallon recipe and starting with the amount of water I am this could be throwing off my numbers??


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[RM-MN]

Watsee. Are you draining out the preboil wort over top of the grains? I crush my own at a home brew shop. I run them through twice. I am not sure of the gap. With that much grain I should be hitting the OG every time.


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With that much grain you should be overshooting your OG. Your LHBS may have the gap on the grain mill set so wide that even double crushed you aren't getting the efficiency you should. If you continue to be frustrated by not hitting your numbers, spend a few bucks and some sweat and get a Corona style mill. Set it as tight as it will go and start cranking the grain through.

 

[DonH]

have you calculated your boil off rate over an hour period? or did you just fudge it? also ambient temp affects this also. I had almost 2 gallons boil off today on my 1 hour boil when i normally have about 1g! ... its 95 outside.

 

[Twang]

Looks like you have a nice concentration of trub in the center. When you whirlpool are you pulling from the downward facing elbow at the bottom of the kettle? (Thinking about how to set mine up)

 

[GuyBob]

Yes. I pull off a 90 street elbow facing down about 1/4" off the bottom. My boil off rate is about 1-2 gallons. I'm thinking if I try doing a recipe calling for 5 gallons it could be throwing off my #'s because I really want 5.5-6 gallons going in fermenter.


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[newnick]

.004 off of a target gravity is not to bad though. I've only done kits so far but they usually have a range of at least .004 for OG. As I mentioned earlier in the post I've cut back on the water a little. I used the same calculator and was coming up short on a couple batches in a row. I then used a different calculator that gave about .5 gal. less water to start with and I've had consistantly higher numbers ever since, as much as .010 above target.
The author of the calculator your using stated that squeezing the bag is not incorporated in the calculation.

 

[monkeyman1000]

Are you checking with hydrometer or a refractometer? I've seen some posts on here and some other sites where people have used 3 different hydrometers and gotten 3 slightly different readings. .004 wouldn't be that far off

 

[Slenderman]

.004 is well within the typical margin of error in terms of testing to determine original gravity. Obviously make sure that you adjust your readings for temperature, ether hydrometer or non-atc refractometer. Not so obviously your kettle thermometer could need recalibrating, making you miss your mash temp by a degree or three. Not a big difference but this is a game of thousandths.

 

[Shack01]

I'm a member of the 'water' camp...

Granted, I'm a relative newby to the BIAB scene - 7 brews, 6 packaged in the past year - and the biggest variable, in MY experience, is water!

Average Boil Off: 1.26gal/hr. Range: 1.00 - 1.40 gallons/hour
Seems to depend on ambient conditions. I brew in the center of my garage. Ambient temperature and wind seem to play a part in my boil-off numbers.

Average Grain Absorption: .24qts/lb. Range: .20 - .32 quarts/pound
This number seems to depend on my technique. My first BIAB, where I just let the bag drain into the kettle, with minimal squeezing, netted me a .27qts/lb absorption rate. The .32qts/lb absorption rate brew was a DIPA, that had a 19lb grain bill that taxed the limits of my equipment (next time I do that brew, I'm doing it as a partial mash! :rockin: ). I have since acquired a large, stainless steel, potato masher to 'squeeze' my bag after the boil and, removing the 'oddballs,' leaves my average at about .22qts/lb.

Brewsmith is a useful TOOL. I use it, HOWEVER, it seems to be geared more towards traditional brewing techniques, and needs to be 'tweaked' to YOUR BIAB brewing experience! To that end, I also use the BIABAbacus to help me calculate water amounts and grain bill.

So, my goal is to BOTTLE/KEG (kegging is my next project) 5 gallons of beer. To that end, I typically work backwards. 5 gallons packaged equals ~ 5.25gal at the end of fermentation, which equals ~ 5.5gal into the fermentor, which equals ~ 6.0gal (AMBIENT TEMP) at end of boil, which equals ~ 7.5 - 8.0 gals starting water volume (depending on grain bill and mash/boil time).

Ultimately, RDWHAHB!

 

[DonH]

awesome write up Shack01!

 

[newnick]

Try this calculator, it has served me well lately.
http://www.copycalc.com/bob/BIAB

 

[GuyBob]

I use a hydrometer. I've tested it and is accurate. I noticed in BeerSmith adjusting equipment is key. I have changed the boil volume to what the the BIAB calculator states recently but have not tried it yet. I think with having the boil volume set at 5.5 instead of 7-8.5 (depending on grain bill) it was giving a higher OG for the recipe in BeerSmith and I was seeing different results live. I will take the info everyone has shared and apply it if I'm still having issues after this next brew day. Thanks for everyone's insight. Mug.


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[DurtyChemist]

H be you considered lowering your mash temp to get more sugars out of the grain? I just did a 15 lb smash and hit 1.058 pre boil of 7.2 gallons and had 71% efficiency for mash and brewhouse. Mash was 145-150F for 75 minutes. 8.5 gallons mash. 7.2 gallons pre boil. 5.5 gallons final volume into the fermenter. I missed my OG by 0.001 for 70% mash efficiency. My research shows 70% for this big of a brew is above and beyond expected but not beyond possible for all grain.

 

[GCPHomebrew]

I would step mash(multi temp), fine crush, mash in only 5 gal, sparge the other 4 and add beano and amylase. One at a time or all. You should have 80-90 efficiency with biab. Your mad temp pro my higher than your thermometer tells you. Slow into the single infusion temp. The temp keeps rising longer than you realize.


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[GCPHomebrew]

Autocorrect. Temperature probably


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