Ugh, low OG.

Rookie brewer here from Va. First, there’s unbelievable amount of knowledge here, so hats off to this place and the people that post here. It's helped me through my first ten or so batches and I've learned some patience...alas, I've gone into freak out mode after attempting my first 5 gallon AG last night.

This was supposed to be an all-cascade IPA. I did my best to glean info from DeathBrewer's awesome AG tutorial. Here's the recipe I went with:

Grain Bill

9lbs. Briess 2-row Brewers Malt
1lbs. 10 oz. Briess Caramel 40L
10 oz. Briess Carapils
8 oz. Briess Victory

11 lbs. 12 oz. total grain

Hop Schedule

60 min – 2.0 cascade pellets (6.4% AA)
30 min – 1.0 cascade pellets (6.4% AA)
2 min. – 1 oz. cascade whole leaf (homegrown)
Flameout – 1 oz. cascade whole leaf (homegrown)
Dry hop – 1 oz. cascade whole leaf (homegrown

Additives

15 min. – 1 tbs. Irish Moss
10 min. – ½ tbs. Wyeast nutrient

Target O.G. – 1.062 at 75% efficiency (wishful thinking)
IBUs - 65
Yeast - Wyeast Northwestern Ale

Mash - I mashed in a nylon bag starting with 3.25 gallons of 168 degree water. By the time I put the lid on, the mash temp was 150. I stirred occasionally (maybe 4 times) for 60 minutes. I lost maybe one degree of heat.

Sparge - I heated 4 gallons of water to 185 degrees, given I wasn't sure how much my stovetop could handle. After removing the grain bag from the wort and letting it drip for a few minutes, I dropped the grain bag in the sparge water and stirred for 10 minutes and then drained the grain bag. Ended up with 5.5 gallons of wort for the boil. Maybe the sparge was too short?

Boil
- Things went pretty much as planned. Boiled for 60 minutes and final wort volume was 4 gallons. My extract experience told me to top off to 5 gallons, realizing afterward that that isn't how my target OG was calculated. ****e.

Aside from that, I was feeling okay about it...everything was fine until….1.030 OG. Dagger. Now I’m just trying to wrap my head around all of the variables and what might have gone wrong. I would need to have mashed at under 40% efficiency to get this OG.

Maybe the top off accounted for much of the loss? Bad grain crush? It looked okay to me.

Bad hydrometer reading? I was hoping so until I took another gravity reading tonight. 18 hours into fermentation, it's down to 1.022. I've learned my lesson in not taking a preboil gravity reading.

Maybe the low efficiency is a combination of these things...or maybe there's one glaring issue? I'm left wondering whether or not to dump the batch and brew again if I can identify one big error. (I'm thinking these will end up at about 2.5 ABV , although the wort tastes pretty good)

Thanks for any input.

A couple things to check right off....

Check your hydrometer in tap water at 60F to make sure it is reading correctly

At what temperature did you take your O.G. reading? Did you correct for temperature? (Temp would have to be way off to be reading .03 points low) But stll something to check.

Even with adding the gallon of water, the gravity at 4.0 gallons would've been under 1.040 for the dilution to make it 1.030.

Did you mix the wort after adding the water? It is possible that if you pulled a sample that was mostly from the top, you got more water and less wort and thus a skewed reading?.....dunno....just grabbing at straws.

In the end, the pre-boil gravity would've really helped figure this out, but you already know that.

In addition to the points Kaz made, I'd ask about your bag that you mashed in. Where the grains nice and loose in there, or where they packed in? You want free movement of water through the grains, and you want to stir like your life depended on it!

Checked the hydrometer and it's working. OG reading was taken at 72-75 degrees. I mixed the wort with the top-off water, but maybe not that thoroughly. Still, sample was taken with a beer thief which probably drew it from at least halfway down the column.

Yooper - your point may have nailed it. I used a 24" x 36" nylon grain bag in a 5 gallon stockpot and the grain was packed in pretty tightly. I also did not stir that much because I did not want to lose my mash temp.

a session IPA ;D

ODA said:

Yooper - your point may have nailed it. I used a 24" x 36" nylon grain bag in a 5 gallon stockpot and the grain was packed in pretty tightly. I also did not stir that much because I did not want to lose my mash temp.

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This is probably it, then. Next time, use an extra bag so that the grain is loose in there! You want the water to totally permeate the grain thoroughly so you can get conversion, and then rinse those sugars out. You need to stir well, so maybe just start with a water that's a few degrees higher so that you don't worry about losing the temperature.

fatguy-littlecoat said:

a session IPA ;D

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If only it were still lawnmower season.

Yooper said:

This is probably it, then. Next time, use an extra bag so that the grain is loose in there! You want the water to totally permeate the grain thoroughly so you can get conversion, and then rinse those sugars out. You need to stir well, so maybe just start with a water that's a few degrees higher so that you don't worry about losing the temperature.

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Thanks for the info, that makes sense. When you say use any extra bag, you're saying split the grain and half and do two mashes so that there's more room to stir?

I, too just started all grain brewing so I feel your pain. Instead of mashing in a 5 gallon stock pot, I place the nylon bag in my bottling bucket. I usually heat the strike water about ten degrees more than needed to account for temperature loss when pouring it in the bucket and then adding the grains. I stir like mad then put one of the fermentation lids lightly on it. The bottling bucket is also swaddled in towels to keep it insulated from heat loss during the hour mash.
Using another 3 gallon or so pot I heat my sparge water in that so when I'm ready, attach the bottling tube to the bucket and slowly collect the first half gallon of wort which is poured back into the bucket. The hose goes into my brew kettle at this point and I proceed to collect the wort.
I've started placing a wide mouth bowl on the top of the mash and I pour my sparge water into it. That way the grain bed isn't disturbed too much. I use a half gallon pitcher to transfer my sparge water.
I'm also able to control the flow of wort into the brew kettle by using the valve on the bottling bucket spigot. I hope this helps! And remember RDWHAHB!

Additionally, I'd be careful with measurements when top off water is involved. I've heard anecdotally that it's tough to get the beer mixed perfectly and thus get an accurate reading.

As a test, drink 10 or 15 of them to see they get you drunk.

manoaction said:

Additionally, I'd be careful with measurements when top off water is involved. I've heard anecdotally that it's tough to get the beer mixed perfectly and thus get an accurate reading.

As a test, drink 10 or 15 of them to see they get you drunk.

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Yeah, seems like taking a pre-top off wort sample and then calculating the dillution would give a more accurate reading.

Will do on the second bit of advice.

So, I rebrewed this recipe last night but went down to 3.5 gallons to make up for lack of equipment space.

This allowed more room for stirring the mash and looser grains in the mash. I also increased mash temp from 150-154 and had more consistent crush.

Got my efficiency up to 67%, which is about what I calculated for. Not great, but after doing some reading and learning that high efficiency doesn't always equate to better beer, I'm pretty satisifed with the process. Of course, the first sip will have the final say. Nice to see some changes make a difference.

Since you're doing biab, may as well crush the grains twice. That will help with efficiency tremendously

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