Help diagnosing low OG in first and second AG

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

sensibull

Well-Known Member
Joined
Aug 15, 2010
Messages
184
Reaction score
9
Location
richmond, va
Just finished my second AG and I thought I had the process down fairly well, but once again I got a much lower OG than expected (made Conroe's Mojave Red, should have been 1.056 or so, mine was around 1.041-1.042).

So, I'm pretty frustrated and don't want to have it happen again. Hoping if I describe my process someone might spot the points where I can increase my efficiency.

Steps

1. Buying the grain bill as specified and having my LHBS do the milling (i.e. not upping the grain bill, though I'm batch sparging. Should I?). Can't afford a mill at this point, but realize this might be an area to increase efficiency.
2. Been using Beersmith to calculate Strike and Sparge amounts. In this case, for about 10lbs of grain, I used 3.15 gallons for dough in and 4.3 gallons for sparging. Water is from a farmhouse well. Tastes great, maybe a little bit high in iron.
3. Dough it at 167, stirred, and mash temp evened out at 153.
4. Held mash temp at 152 for 60 min, as the recipe called for. Using a 10g rubbermaid with bazooka tube, per Flyguy's guide.
4. At 60 min. mark, vorlaufed a few pitchers of the first runnings, and then immediately drained the wort into my brew pot.
5. Sparged with 4.3 gallons at 172 degrees. Pour water in over a strainer. Now this is where I had problems. The temp of the grains + sparge water never hit 168. It only made it to 162 or so. Why? Only waited about 2-3 minutes**, vorlaufed again, and then opened the valve to collect the second runnings in the brew pot**. Collected a little over 6 gallons, with quite a bit still left in the mash tun.
6. Boiled for 60 minutes as normal, etc. etc.

Now, after a bit more reading, it seems the points marked with ** are where I made my errors, meaning I should let the sparge water sit longer and I should be draining the sparge water a lot more slowly. I also need to figure out how to properly mash out. Could those two things entirely explain my low OG?

Many thanks in advance for any advice offered.
 
First, did you temperature correct your SG readings?

Second how does the crush from your LHBS look? Last one from mine had a lot of whole kernels in it. I should have run it through my Corona again.

If you come out low, you can always add some sugar or dextrose.
 
First, did you temperature correct your SG readings?

Second how does the crush from your LHBS look? Last one from mine had a lot of whole kernels in it. I should have run it through my Corona again.

If you come out low, you can always add some sugar or dextrose.

I did temp correct the readings. Not sure I'm experienced enough to evaluate a crush, but I honestly didn't look at it too closely before poring it in the tun. Seemed OK, but I don't know.

I am considering adding a 1/2 lb. of dextrose at high krausen. Conroe (member here, recipe author) suggested against it, because it would probably make the beer finish too dry, I'd like the beer to have a little alcohol in it though :drunk:.
 
Generally, a poor crush is the cause of efficiency issues. Sometimes water chemistry plays a part.

Did you get roughly the same efficiency last time? What I'd suggest is figuring out your efficiency (Beersmith makes it easy) and just planning on that % for your future batches. My efficiency is always 72%- it's not good or bad, it's just what it is. If you plan your recipes based on your own efficiency, your beer will come out every time.

That said, I don't understand #5 about your sparge. Your batch sparging? But pouring through a strainer? I'm not sure I understand. Can you explain exactly what your process is? You can add hot enough water to get your grainbed to 168. For me today, that was 10 quarts of 187 degree water. (I did a 10 gallon batch today)
 
Are you stirring after you add your sparge water? I have only done two AG brews so far, and I'm getting 77-81%. I stir for about two minutes after adding the sparge water.

I'm certainly no expert...just trying to help.
 
Are you stirring after you add your sparge water? I have only done two AG brews so far, and I'm getting 77-81%. I stir for about two minutes after adding the sparge water.

I'm certainly no expert...just trying to help.


I stir the heck out of the mash (2 or 3 times) and often let it sit longer than 60 minutes. I also stir the sparge and let it sit 5 minutes or so. I don't know if it makes any difference but I have consistently had at least the recipe OG sometimes more.

Just the way I do it, and I get good results.
 
Generally, a poor crush is the cause of efficiency issues. Sometimes water chemistry plays a part.

Did you get roughly the same efficiency last time? What I'd suggest is figuring out your efficiency (Beersmith makes it easy) and just planning on that % for your future batches. My efficiency is always 72%- it's not good or bad, it's just what it is. If you plan your recipes based on your own efficiency, your beer will come out every time.

That said, I don't understand #5 about your sparge. Your batch sparging? But pouring through a strainer? I'm not sure I understand. Can you explain exactly what your process is? You can add hot enough water to get your grainbed to 168. For me today, that was 10 quarts of 187 degree water. (I did a 10 gallon batch today)

Something I read somewhere suggested it wasn't a good idea to just dump the whole amount of sparge water straight into the mash tun -- that it would create a channel through the grain and not pick up enough sugars/create adequate wort along the way, so I poured in the sparge water through a strainer to deflect/decrease the impact of the water, so to speak. Is that not proper technique? I guess if I was letting the sparge water sit longer, as I should be, it wouldn't matter so much...

I also suppose I was hesitant to just keep adding more hot water (to hit 168) because I thought that would water down the wort and exacerbate my low gravity problems.

I just played around with Beersmith a bit and figured out how a scale a recipe for different efficiencies. That will certainly help me in the future. Thank you.
 
Are you stirring after you add your sparge water? I have only done two AG brews so far, and I'm getting 77-81%. I stir for about two minutes after adding the sparge water.

I'm certainly no expert...just trying to help.

Thanks for the tip. I only stirred at dough in, not during the sparge.
 
Something I read somewhere suggested it wasn't a good idea to just dump the whole amount of sparge water straight into the mash tun -- that it would create a channel through the grain and not pick up enough sugars/create adequate wort along the way, so I poured in the sparge water through a strainer to deflect/decrease the impact of the water, so to speak. Is that not proper technique? I guess if I was letting the sparge water sit longer, as I should be, it wouldn't matter so much...

I would think that channelization would have a bigger impact if you were doing a continuous sparge as opposed to a batch sparge. I dump my batch water in, stir it up, let it sit for 5 mins or so, vorlauf, then drain.
 
Something I read somewhere suggested it wasn't a good idea to just dump the whole amount of sparge water straight into the mash tun -- that it would create a channel through the grain and not pick up enough sugars/create adequate wort along the way, so I poured in the sparge water through a strainer to deflect/decrease the impact of the water, so to speak. Is that not proper technique? I guess if I was letting the sparge water sit longer, as I should be, it wouldn't matter so much...

I also suppose I was hesitant to just keep adding more hot water (to hit 168) because I thought that would water down the wort and exacerbate my low gravity problems.

I just played around with Beersmith a bit and figured out how a scale a recipe for different efficiencies. That will certainly help me in the future. Thank you.

I would think that channelization would have a bigger impact if you were doing a continuous sparge as opposed to a batch sparge. I dump my batch water in, stir it up, let it sit for 5 mins or so, vorlauf, then drain.

Right. If you're batch sparging, just dump it in and stir like a madman. You can add water, even boiling water, to get your grain bed to 168 during the first addition of sparge water. That might help you quite a bit.
 
That's not a tip. It's a revelation. If you batch sparge, you stir the hell out of the mash again after the sparge water goes in. The stuff you read is related to fly sparging and can be disregarded. If you want the temp to get near 168, you need to sparge with 185F water.
 
Well, I'm still at a loss. Just brewed up BierMuncher's Centennial Blonde, which has what should be a very doable 70% efficiency built into the recipe and I still didn't quite hit my number (1.037 OG instead of 1.040).

I held the proper mash temp for the proper time. Stirred like mad during both dough in and sparge. Hit my mashout temp. Used spring water this time. Not sure what else I can do but increase my grain bill, I guess, but it bums me out to have to spend more on what should be a correctable issue...

What's even stranger is that, according to the online calculator I used, I had a 1.035 pre boil gravity (1.016 at 150 degrees). You'd think I'd gain more than .002 points over a 60 minute boil.
 
Well, I would first ask that you evaluate the crush that you are getting from your local. some have good grain mills and others have really crappy ones. See here https://www.homebrewtalk.com/wiki/index.php/Evaluating_the_Crush
You can also take a picture next time and upload it into this thread so that we can help you.

Can you also give us an idea of what your boil-off rate is? Sounds like you are using beersmith to get your volume close to 6 gallons pre-boil? Are you sure that you are going into fermenter (post boil) w/ 5 gallons? like you say, .002 points over 60 minutes is really low. boiling 6 gallons down to 5 is boiling off 16%.
 
I'll be sure to take a picture of the grain next time. I actually meant to today, but forgot in the process of the brew.

As far as I know, I went from somewhere just north of 6 gallons preboil to a little over 5 gallons post boil. I have measurement lines on both my pot and my bucket.
 
How sure of you of your temp readings? When I upgraded to a nicer thermometer, my numbers were much more appropriate even though I didn't change any of my normal steps/procedures. Being able to trust the temp measurement was crucial for me.
 
Thanks for the input. I've been using a decent digital liquid thermometer, so hopefully that is as accurate as I need to be.
 

Latest posts

Back
Top