Really low OG on all-grain attempt

[pdm1982]

I just brewed my 3rd all-grain beer this past weekend. From what I could tell on my hydrometer, I missed my OG by about 12 points (1.040 instead of 1.052). Beersmith estimated my brewhouse efficiency at about 54%. One positive is that I nailed my water volumes. I'm now just trying to troubleshoot what I did wrong that caused such a gross error. Here are some of my theories:

1. Hydrometer reading. I tested my hydrometer and it is accurate, however, I had to use an entire pitcher of water to get a good reading. I learned that my test tube and wine theif are too narrow and the hydrometer will stick to the sides or lean. I had a hell of a time just getting a reading on plain tap water so it stands to reason that maybe my reading from last weekend was off some. That could mean I was closer to my target or even farther away so there's no good conclusion to be drawn from this. I'm buying a refractometer to resolve some of this issue for future batches.

2. Doughing-in. My brown bag of grain ripped when I was pouring and a lot of grain went in really fast. I used two stirring paddles to try to make sure it broke up and mixed properly but who knows.

3. Mash. I missed a setting in Beersmith that adjusts strike water temps for my equipment so I was low after doughing-in. I just quickly brought 2 quarts of the sparge water up to a boil then added and stirred it. It seemed to get me closer to 153 so I let it mash for an hour.

4. Sparge. I read dennybrew's batch sparge method and followed it. I'm at a loss for what I could have done wrong here. I added half of my sparge water (180 degrees) and stirred it. Recirculated 2 quarts then slowly drained it. Then I repeated the same thing with the other half. I ended up with just about a quart more wort than I planned for but other than that I thought it went well.

That's about as far as I know how to troubleshoot such a low gravity. It's especially surprising when I was near my volume going into the pot and into the fermenter. I really want to learn from this but I'm at a loss. Any advice is appreciated.

 

[Black Island Brewer]

Three things popped into my head - there could be other things as well, and I'm sure you'll get a lot of help! First, there is the crush - it's one of the usual culprits for low efficiency. A finer crush could result in better conversion, as more of the starch granules are exposed to enzymatic action. Second, you may have had dough balls - dry spots in the mash resulting from the quick addition of your grist. Dry=no conversion. How did your mash look when you dumped it? Third, although I've never batch sparged, I understand that once you recirculate, you can open it up wide open when you drain the tun, since you're not worrying about channeling. If you drained slowly, could that affect how much of the sugars get "unstuck" from the grain as it drains? I don't know, just thinking out loud...

 

[BigFloyd]

Another piece of gear to check is the mash thermometer. Some of the floating ones are really off. I've got one that I don't use anymore that reads 7*F high.

How much do you stir when you dough in? That has an impact. You can also stir again when you do the batch sparge and let it sit 10-15 min before draining. That may help.

Crush also has a role here.

 

[pdm1982]

Since it's a wheat beer I was using 1 lb of rice hulls. I didn't fully open my sparge valve because I was unsure of how much suction that would put on the grain and I had no idea how well the hulls would help or not. So I took it slow and easy on the drain.

 

[pdm1982]

I wondered about waiting 10 minutes to drain it after stirring in the sparge water. Might be something I try on the next batch. I used a standard thermometer. I just poke it into the mash near the middle. I notice the temp rises the deeper I go into the mash.

 

[pdm1982]

I wish I would have inspected the grain better (before and after). I wouldn't be able to recognize a bad crush so I should probably get educated on that. As far as went I dumped my spent grains I didn't notice any dry spots. Also, I always sample the spent grains to see if they are still sweet. I got no flavor so I took it as a good sign.

 

[Whattawort]

+1 on the crush. It took me 3 or 4 batches before I dialed that in to get better efficiency. It's also good to note the temp of the mash in the deepest part of the MLT and the consistency of the temp throughout the mash. My first batch was uber hot in the deeper middle part and spot on towards the shallower out part. I have adjust my strike water temps now to aim for an appx 153F in the deepest part of my MLT since that's where the bulk of the grain lies.

 

[pdm1982]

So should I be opening the cooler and checking the mash temp every so often? I was concerned about losing heat as it was chilly in my garage. I threw the lid on as soon as I got the reading I wanted and didn't check it again. Something to think about for next time...

 

[BigFloyd]

How long did you stir when you mashed in? Next time, use a timer and give it a full 8-10 minutes. That's a bunch of stirring, but it really does help.

Stir when you batch sparge for about 3 minutes then let it sit 10-15 min before vorlauf and drain.

 

[Bobby_M]

Did you drain the mash tun fully before adding any sparge water?

 

[BigFloyd]

Did you drain the mash tun fully before adding any sparge water?

+1. I forgot about that one since I've been E-BIABing for a while.

After it drains, tilt the back of the cooler up and put something under it so that the end with the valve is lower. You may get quite a bit more goodness out that way.

 

[pdm1982]

Yep I did let it drain completely but I didn't tilt it. My mash tun has 2 quarts dead space at the bottom and I had adjusted for this in Beersmith. I'm not sure if tilting the tun is then necessary but I might give it a shot next time around.