Obsessing over low original gravity readings.

First of all I apologize for my long windedness. I pulled my latest sample for an original gravity reading directly post chill and after dumping to primary. I use a turkey baster to pull the sample. I am hoping that some of the more dense wort sinks really quickly to the lower depths of the bucket and that the few inches of turkey baster I submerge to draw the sample are not pulling a true representation. It seems as though it should be well mixed directly after transfer. If the readings are correct, I am getting less than 65% efficiency with all grain. I have batched sparged and also tried slowly and meticulously fly sparging this most recent batch by pouring off the back of a ladle to see if I could find any differences in outcome. This is three batches in and my beer has been turning out good, but all three have come in low by around 6 points. I am not too concerned at how much alcohol is produced, but for efficiency sake I want to know that when I am shooting for a gravity I can reasonably obtain it instead of adding money onto the grain bill. It is a fairly important piece of the equation afterall.

I have been using a plastic "yard" style container (for my Michigan brethren it is one of the tall frozen daiquiri drink vessels that you can get at Detroit Tiger games) that is basically like an elongated erlenmeyer or perhaps a "bong" shape with a bubble at the bottom and a square neck. I just bought a more traditional cylinder today at the LHBS, although i don't see why the shape of that daiquiri container would make a difference. I think I am clutching at straws to make myself believe that I am not truly coming up short. Maybe my system is just not efficient. I am using a rectangular cooler with a washer hose manifold and mashing and sparging with appropriate volumes. I have grown to dread the gravity reading.

Why dread? If you are getting 65% efficiency consistently, then plan around getting 65% and you won't come up under the OG of your recipe.

From there, you can try troubleshooting and, if your start hitting above 65%, you can introduce a bit more water at the start of your boil to bring your numbers back down. Eventually, if you start hitting a new efficiency consistently, that becomes your new baseline.

Hitting your target gravity is a lot more important than hitting your target efficiency.

We get this every day...

It's a pretty common issue for ANYONE topping off with water in the fermenter (and that includes partial mashes, extract or all grain revcipes) to have an error in reading the OG...In fact, it is actually nearly impossible to mix the wort and the top off water in a way to get an accurate OG reading...

Brewers get a low reading if they get more of the top off water than the wort, conversely they get a higher number if they grabbed more of the extract than the top off water in their sample.

When I am doing an extract with grain recipe I make sure to stir for a minimum of 5 minutes (whipping up a froth to aerate as well) before I draw a grav sample and pitch my yeast....It really is an effort to integrate the wort with the top off water...This is a fairly common new brewer issue we get on here...unless you under or over topped off or the final volume for the kit was 5 gallons and you topped off to 5.5, then the issue, sorry to say, is "operator error"

If your target volume was correct, then it will be fine.

More than likely your true OG is really what it's supposed to be. And it will mix itself fine during fermentation.

While i agree whith MalFet, I completely understand your point. Being on limited income at the moment i sympathise with not wanting to waste grain on low efficiency. Not being an expert, however everything i see on here says look at your grain crush first. Mabye there is a place to increase. better crush =better efficiency. I got lucky and my lhbs cares more for good beer than more sales so i got 75% on my 1st 2 ag batches.

i am actually not topping up. not at all. i use what i have post boil and have been nailing my five gallon volume within +/- a quart. i have considered the crush as a possible factor. that will surely be my next experiment. i would hate to think that my LHBS has their mill set skimpy to promote more poundage sold, but who knows. after that, i may try making a different manifold. i currently use a 48 quart cooler with the steel braid washer hose in a looping continuous circuit. any thoughts on manifolds? i know everyone has his own opinion, and i have been reading and learning some great things here. thanks people, i appreciate your input. one way or the other i will get her figured out. rest assured i am still having fun.

Many LHBS mill a little more coarse to prevent stuck sparges (or so they say). This is where having your own mill is nice, you can easily manipulate the crush to see if it makes a difference. You could ask the LHBS to run it through the mill twice if they aren't willing to adjust the setting on the mill.

Also, on manifolds - they will make a difference for fly sparging, but for batch sparging it doesn't really matter. Since you got about the same efficiency using a batch as a fly sparge, I'd say that's probably not the issue.

I'd personally start with the crush - as that tends to bring the biggest gains, then look at mash pH and temps as well as sparge temp (try to get the grain bed to 170 for sparge).

MarkChillwort said:

I use a turkey baster to pull the sample. I am hoping that some of the more dense wort sinks really quickly to the lower depths of the bucket and that the few inches of turkey baster I submerge to draw the sample are not pulling a true representation. .

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Well this is what was confusing to me....that sounds like you're topping off. In terms of full volume ag boils, there's really NOT denser and less denser wort sinking in your fermenter...there's only wort, and it should have the same gravity reading all the way through. It's all been boiled together so it should be all the same all the way through. Boiling would have mixed the different runnings into on homogeneous volume.

Getting that out of your picture you need to look at your crush.

I was getting 65% consistently and just stuck with that number when formulating recipes etc. Its not too much money ($2-3 extra) to make up for a small hit in efficiency. I've got a grain mill now and with the process I'm at 80%. If you think the LHBS doesnt mill very well, ask them to do it twice. I bet you'll see a jump after that. Also, make sure you are completely draining your MLT, liquid left behind is sugar left behind.

I actually feed my own grain down their belt driven grinder. Would you recommend that next time I shoot it through twice? Can you over crush and then end up with pulverized bits of things that will negatively impact flavor or is it perfectly harmless as well as potentially beneficial?

Take a preboil gravity and compensate by adding DME. You'll hit your gravity everytime if you do it right.

MarkChillwort said:

I actually feed my own grain down their belt driven grinder. Would you recommend that next time I shoot it through twice? Can you over crush and then end up with pulverized bits of things that will negatively impact flavor or is it perfectly harmless as well as potentially beneficial?

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the only issue that "overcrush"ing would present is that you're more likely to get a stuck sparge. Oversparging, where you continue to run water through the grain after you've extracted all the sugars, is where you'd run the risk of extracting tannins and cause astringency.

I say run it through twice and see if you increase efficiency. Also, be careful when you start pulling your first runnings from the MLT - you want to start slow so that the grain bed gets set. If you let it run out quickly you risk overcompacting the grain bed and getting a stuck sparge.

Crush is a good candidate, but at the end of the day efficiency can be a challenge to troubleshoot thoroughly. If you want to be systematic about finding what is limiting your numbers, I'd strongly recommend Kaiser's troubleshooting guide.

I would plan your next recipe for 65% eff. See if you hit your numbers as planned. If you do then you know your process is solid. You can then look into changing something one piece at a time. Your manifold won't make much difference, I use a stainless braid and get 80% eff.

I would suspect crush. After I got my mill it eliminated a lot of potential variables since I used to order grain from many different places.

Milled my stuff twice and brewed today. Also mashed for 90 minutes instead of my usual 60. As well i drained the box much slower so as not to compact the grain bed. Got up to 75 percent efficiency this time. Thanks brewmeisters for all of your replies. I have another lovely golden lawn mower beer in the fermenter right now and I am just giddy with excitement. Drank an 11 days in the bottle IPA after and it was fantastic too. It is so hard to leave them sit...