Way too low OG (BIAB)

So I did an IPA yesterday with 14lbs of 2 row and a lb or so of crystal. I got an OG of 1.042 measured at 78 degrees.

I believe my issue was a low mash temp, coupled with the fact that the bag I was using didn't allow for good contact with the water because it was too small and sort of "squeezed the grain". Next time I am going to try and move away from BIAB or I'll really have to rethink my BIAB approach, but what now? BeerSmith tells me that's less than 40% efficiency.

Is 1.042 just way too low for this beer? Should I boil up a pound of Extra Light DME.

sure. If your dissatisfied with the results go
ahead. Or you could accept your fate and attribute it to growing pains and drink your session IPA. Recheck your process specifically crush and make sure to properly wet all the grains during the mash and don't try to rush things if you mash low let it go longer. Beer takes weeks to make so spending a few extra minutes or even hours brewing is nothing in the long run.

Carter,
By any chance did you add some water to your fermentor after transferring the wort, and just before taking the hydrometer reading?
If so, the low gravity reaing is probably due to the wort not being mixed well, and the fresh water is at the top.

>>I believe my issue was a low mash temp,

How low? How long was the mash? How good was the crush?

>>coupled with the fact that the bag I was using didn't allow for good contact with the water because it was too small and sort of "squeezed the grain". Next time I am going to try and move away from BIAB or I'll really have to rethink my BIAB approach,

It's not that BIAB doesn't work, it works great, but you have to do it correctly. Why move away from it? Just make sure you have the correct size pot, and a correct size bag.

ArcLight said:

Carter,
By any chance did you add some water to your fermentor after transferring the wort, and just before taking the hydrometer reading?
If so, the low gravity reaing is probably due to the wort not being mixed well, and the fresh water is at the top.

>>I believe my issue was a low mash temp,

How low? How long was the mash? How good was the crush?

>>coupled with the fact that the bag I was using didn't allow for good contact with the water because it was too small and sort of "squeezed the grain". Next time I am going to try and move away from BIAB or I'll really have to rethink my BIAB approach,

It's not that BIAB doesn't work, it works great, but you have to do it correctly. Why move away from it? Just make sure you have the correct size pot, and a correct size bag.

Click to expand...

Thanks for the help. To answer some of these questions. I ordered my grain from love2brew already crushed. I examined the grain and it was indeed well crushed.

My mash was supposed to be at 156 for an hour. I had to run an errand and when I got back an hour later it had fallen to 130F, It was 156 when I left. So I heated my mash tun and added hat water until I was at 155-160. I let that sit for about 20 more minutes. I then sparged with 170 degree water. I know I should have let it sit longer, but I had work early this morning and new my brew day was already running long.

I think my issue was that when I left the mash for an hour the grain had not yet fully warmed. In the past I have never had that much thermal loss, so I think the grain just wasn't up to temperature yet. In the past my mash tun (8 gallon AL pot) retains heat well because I wrap it in many towels. So basically I mashed at a really low temp.

Where are people getting bags for BIAB, mine is not wide enough to for my pot and therefore it's really a pain.

Also how much DME would I want to add to take my 1.042 to a more respectable 1.055 or so? Currently there are 5.25 gallons in my fermentor.

Thanks for the advice!

Also something unique I do on my BIAB is that I actually lift the bag up after my mash and then sparge with it hanging above my brew kettle. I think this is a bad idea since most seem to just turn up the kettle to sparge temp and finish the mash like that. I think next time I will try this method instead.

How much water did you use total? With BIAB the less water you have in the mash the worse your efficiency is going to be (in my experience. You also need a bag that your kettle can fit in. If you're doing 5 gallon batches in an 8 gallon pot you can't fit enough mash water in there with the grain especially with your grainbill. I wouldn't add DME at this point, but to get to 1.055 you'd need 1.5 lbs of DME (you would need to boil and cool it before adding to a fermenter). With an 8 gallon kettle you'd be better off doing partial mash batches or 3 gallon BIAB batches.

There's a member on here that makes custom BIAB bags. Otherwise go to Walmart and get some voile curtain material and sew up a bag.

I'm pretty committed to All Grain. It just feels more pure, and since I keg and try to keep an active rotation going I do like to have a full five gallons. I think the question for me is whether my sparging method actually works. I will likely get a 10 gallon Rubbermaid to do a proper mash, since my kettle is not large enough.

That sounds like a good plan, i think there are quite a few brewers that batch sparge with only a mash tun and kettle.

I didnt find that sparging by pouring through the grain bag did anything, however many biab brewers dunk sparge in a second vessel with great results.

A couple thoughts...

1: With BIAB you really do not need to be sparging. Put the full volume of water in your kettle and then mash is with all your grains. there are calculators which help you figure out your water. (Usually around 7.5 gal for a 5 gal batch)

2: Your grains may seem to be crushed but with BIAB they REALLY need to be crushed. Since you will not be sparging using the grain as your filter, the crush can be very fine and drastically improves your efficiency. Many LHBS's do not offer a real fine crush so they can sell more grain. Not sure how your crush was but this does impact efficiency.

3: There are folks on here who sell nice bags. However, if you know someone who sews, you can buy a yard of VOILE fabric and sew it into a big bag. That is what I did and my bag has no issues holding whatever grains I need for my 5 gal batches.

Well I just ordered a 10 gallon cooler, and stainless steel valve assembly. I am hoping to try again this weekend.

Still I am disappointed about the batch I just made. I am wondering a few things:

1) How long should I ferment? I was planning on 2 week primary and then 3 days dry hop in secondary. I don't even think I should dry hop since their won't be much to balance the hop flavor of this IPA.

2) What will be the effect besides low ABV of my low mash temp?

3) Apart from the risk of contamination what are the reasons not the boil and cool a pound of extra light DME and add it to the bucket?

Thanks, and I'm super excited to get my cooler and do a real mash this weekend.

With a 14+ lb grainbill I typically hit the low 170's. I used to only hit 1.040 to 1.050 with LHBS crush and until I purchased my BC and tightened it up to 35 thousands my efficiency finally turned around. It's all in the crush baby!

If the mash started at 156, it would've mostly or totally converted by the time it hit 130. That's still within the range of beta amylase. The result should be good efficiency but a thin bodied beer.

I also have issues holding temps when I BIAB. Sometimes I'll turn on my burner for a few minutes about halfway through to bump it up. I have a false bottom that prevents burning the bag when doing this. It also lets me sparge before removing the bag.

Do you squeeze your bag or twist it while it hangs above the kettle? Doing so could add up to 1-2 quarts of wort. I lose 0.5 gallon of water per 10b grain squeezing hard. Not squeezing loses about 1 gallon per 10lb grain.

In my experience, 14-16lb grain is about the limit for BIAB. I've done a 19 lb barleywine grain bill, and had under 70% efficiency. Normally, I'll get 75-80% efficiency. Its just too hard to lift and drain. Moving forward, I'll probably limit myself to 15lb and use sugar/DME for high gravity beers.

I think the crush might have been part of the issue. I am looking either a monster mill or corona style grain crusher to help move my AG process forward. I am leaning towards the MM since I know I will want to get it eventually anyway.

Hey - just looking around as both my recent BIAB attempts seemed to have very low efficiency.

I tried to do a 4-gallon batch of an IPA, needed 1.055 OG, ended up with 1.035.

Then I tried a 5-gallon "Dragon's Milk"-ish clone, needed 1.080, only got 1.045...

I was very careful both times with water temperatures, time, etc. Both were 60-minute mashes, no sparging (used the full volume). In both instances I added a half-gallon top-up to adjust for boil-off...

My thought is that the grind isn't fine enough - I use the mill at the LHBS, but perhaps I should just run it through a second (or third) time next time? Would that make enough of a difference?

The bag I'm using might also be too small - I have a 9.5 gallon pot, but the bag only stretches across half the opening, so I clip it in 3 places to hold it in place. Would a larger one be better?

Two things that I have done to gain biab OG readings:

1. Squeeze the bag!
2. Remove the false bottom and give the wort a solid stir
3. Make sure you cool your sample wort before reading!!!! This is probably the most important step. Failure to do this will result is way off readings. Slowly pour over a frozen ice pack (so that you'll not dilute your sample) and into a jar until cool. Transfer to your sampling container and measure. Since you are about to boil, you can return your sample wort to the kettle if your measuring equipment was clean to begin with.

Good luck!

Yes to both of your questions. A fine crush works a lot better for BIAB -- I try to crush so that the grain resembles cornmeal, much finer than if I were using a three vessel system. And it's fairly important to use a big bag so the liquor circulates through the grain. A bag the size of your pot is optimal. If nothing else, go get a yard or two of voile fabric at a craft store and, if you're careful, you can use it without even sewing.

Other stuff: make sure you are fully incorporating the grain (no dry grain or dough balls); make extra sure your thermometer is accurate (calibrate in ice water and boiling water); add a bit of calcium chloride and acid to pale grists (either sauermalz, acid blend, or in a pinch, lemon juice).

cannman said:

Two things that I have done to gain biab OG readings:

1. Squeeze the bag!
2. Remove the false bottom and give the wort a solid stir
3. Make sure you cool your sample wort before reading!!!! This is probably the most important step. Failure to do this will result is way off readings. Slowly pour over a frozen ice pack (so that you'll not dilute your sample) and into a jar until cool. Transfer to your sampling container and measure. Since you are about to boil, you can return your sample wort to the kettle if your measuring equipment was clean to begin with.

Good luck!

Click to expand...

No "false bottom" in my case, but I didn't squeeze too much in either case, so I'll try that next time. I measured my OG when I transferred into the carboy at 30C, so maybe I'll wait a bit longer next time.

My grain is usually just broken up a little bit - much of it looks intact. I think that's a big issue if it's supposed to look more like cornmeal!

gfinockio said:

My grain is usually just broken up a little bit - much of it looks intact. I think that's a big issue if it's supposed to look more like cornmeal!

Click to expand...

Yeah, that will drastically lower efficiency. I use an inexpensive Corona mill, which isn't ideal for traditional 3-vessel systems, but works great for BIAB, because you can just shred the grain to bits very easily.

gfinockio said:

No "false bottom" in my case, but I didn't squeeze too much in either case, so I'll try that next time. I measured my OG when I transferred into the carboy at 30C, so maybe I'll wait a bit longer next time.

My grain is usually just broken up a little bit - much of it looks intact. I think that's a big issue if it's supposed to look more like cornmeal!

Click to expand...

If you're milling your own, I'd go ultra fine. Not flour fine, but almost like steel cut oats. This is only because you are using BIAB and have a way to limit your trub with the bag. This should increase your efficiency...

I do BIAB and from day one have gotten higher efficiency than planned for. A few things I do:
1) I ask my LHBS to double-mill all the grain.
2) yes, definitely have a bag that fits well in the pot, almost like there's no bag in it at all. I stir like crazy when I mash in, then once or twice throughout the hour long mash. There shouldn't be any solid chunks/dough-balls.
3) when I pull the bag, I drain and squeeze the crap out of it. Then put the bag back into my mash-cooler, add more hot water (my dunk-batch-sparge of sorts), and repeat. My batch sparge water is usually about 170 deg, and I let it soak for about 10 mins, again - stir well when you add the water, maybe once throughout, then squeeze like crazy at the end.

Don't be afraid of tannins or anything from squeezing. Hope this helps.


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