Extremely Low OG. What happened? (AG)

Here's the recipe. It's a wit, straight from the book "Brewing Classic Styles".

I've brewed this recipe before and it turned out phenomenal.

This time, I'm on the same equipment (your typical 10gallon cooler mash tun). I hit all my temps and everything went perfect. Until I tasted the wort. It was hardly sweet at all. So, I took a reading and uh oh... 1.024. The volume is 7.5 gallons (pre-boil). The OG (for 5 gallons) is supposed to be 1.058!

Is this really far off? Should I even bother with trying to boil it down to 5 gallons? I double checked my hydrometer and my thermometer and everything is fine.

Other details:
- I fly sparged (same as I did last time) and it took a full hour to get 7.5 gallons. I went nice and slow.
- I did a 60min infusion at 154.
- I mixed it like crazy.
- I sparged for about an hour (same as last time)
- Last time, with the same equipment and the same recipe, I got 78% efficiency.
- The grain was milled hours before they were used. I didn't check the crush. My LHBS always just does it for me.

Thoughts? 1.024 just seems so low, even considering there's 2 gallons of wort to boil off. According to this calculator, I'd have to boil down to 3.1 gallons to get to 1.058. And that doesn't sound right.

jeremydgreat said:

Here's the recipe. It's a wit, straight from the book "Brewing Classic Styles".

I've brewed this recipe before and it turned out phenomenal.

This time, I'm on the same equipment (your typical 10gallon cooler mash tun). I hit all my temps and everything went perfect. Until I tasted the wort. It was hardly sweet at all. So, I took a reading and uh oh... 1.024. The volume is 7.5 gallons (pre-boil). The OG (for 5 gallons) is supposed to be 1.058!

Is this really far off? Should I even bother with trying to boil it down to 5 gallons? I double checked my hydrometer and my thermometer and everything is fine.

Other details:
- I fly sparged (same as I did last time)
- I did a 60min infusion at 154.
- I sparged for about an hour (same as last time)

Thoughts? 1.024 just seems so low, even considering there's 2 gallons of wort to boil off. According to this calculator, I'd have to boil down to 3.1 gallons to get to 1.058. And that doesn't sound right.

Click to expand...

I didn't run the numbers in beersmith, but yes, looks pretty low. How was your grain crush? If you bought your grain pre-crushed, it start losing a lot after the first week or 2. If you crushed it yourself, did you use the same equipment as last time? How did everything look?

The mash is a bit high for a wit in my opinion, but that shouldn't matter for efficiency... What about your sparge and lauter rate? Did you go nice and slow? Did you make sure you mixed the grain well when you mashed in?

In my opinion, differences here have to do with attention to technique with the process, and also when the grain was crushed/good weights and all that. But don't worry too much, a wit depends a lot on the adjuncts (BCS has orange peel and coriander if i remember correctly) and the yeast to add flavor, so run a calculator and boost your OG by simple sugars (corn sugar, etc) to get what you need.

Good luck! Don't worry, same thing happened to me last wit, I think I got a bad crush on some of my grain. I boosted with corn sugar and it turned out fine.

Your sparge may have not hit all the grain and tunneled, only washing a small amount of the grist.

Bad crush,

PH maybe?

Or

Did you make sure the wort you tested with the hydrometer was cooled to the hydrometer's calibration point? That was my mistake when I was off that far.

As for using it that would best be answered by someone with more experience than I. I personally would double check the wort after it was stirred well and your sample is cooled. If it is still way off I, and it is just my way of fixing a big problem with my numbers, would just start again.

It's very possible. Two things can come into play.

That recipe uses half unmalted grain (the flaked wheat). In theory, when using modern brewing malts, there is enough extra enzymes for the flaked wheat to borrow and get itself converted. If you had a poor crush on your malted grain, this could be a big problem getting that wheat to convert.

The other is that flaked grain gets gummy. If you did not use a sparge aid like rice hulls, it is possible you couldn't efficiently lauter and sparge, leaving much of the sugar behind in the tun.

Go ahead and brew the beer. You can always bump it with a kicker of Alexanders Wheat Malt to get it where it needs to be.

I've updated the original comment to answer your questions. I am going bonkers here. Last time, I got 78% efficiency. Same recipe. Same equipment. Same sparge method. This time, 43%?

The fisrt thing you whant to understand is: Where I've lost my efficency? in mashing process or during sparging?

An Iodine test at the end of the mashinr rest can't tell you what is your efficency but at least if you have converted all the starches in your mashtun. Than of course you have to check mash pH, crusch of the grain etc..

Sounds like bad crush or bad sparge. I have read about sparge water filtering down the sides of the mash and leaving behind most of the sugars. I think that is probably what happened, possibly due to a sticky mash caused by the wheat. Did you vorlauf the mash before you started sparging?

That is a massive OG swing. Have you thought about "obvious" things like:

When have you last calibrated your thermometer(s) and hydrometer? Maybe your mash temp was way off.

Are you sure you got the right amount and type of grain? It was all crushed properly?

WIth a OG delta of that magnitude I'd take a step back and eliminate any major brain-farts. Hard to explain a swing that big due to "subtle" issues.

My vote without further info would be for a bad crush. On one of my recent grain brews I had ordered my grains milled and they came to me un-milled. I spent a few hours on my knees with a rolling pin but in the end I did a piss poor job of crushing them and ended up with about 35% efficiency. Otherwise generally hitting 75%.

FOLLOW UP:

Okay, so I brewed the exact same recipe, methods, and equipment. The one thing I changed about the grain bill, was I took the rice hulls DOWN from 1lb to .5lb. Once again, I hit all my temp targets and fly sparged over a full hour.

Batch #2 had... 78.5% efficiency.

I talked to my brewing buddy and asked him what he remembered about batch #1 from the day before. From what we could remember, there were 2 things different about the grain: 1) the grain wasn't quite crushed as much (less white-floury grain guts exposed) and 2) instead of running just the barley through the mill, we ran the flaked grains and the rice hulls. In batch #2 it was all just really mixed together well. in batch #1 we really mixed the grain vigorously... in the mash tun (in the bag they were layered- barley, flaked grains, and rice hulls on top). While sparging batch #1, there were actually rice hulls floating at the top. Batch #2 had complete consistency.

THE LESSONS:

• 1lb of rice hulls is really a lot. The water will fly right through the grist and quick-moving water means higher chance of channeling. Especially on a tall mash tun. Better to use .5lbs.
• Mix. It. Up. When using different types of grain (kernels, flakes, and hulls) it's really important that it all gets mixed well outside of the mash tun.
• Check the crush yourself (in batch #1 I didn't watch my LHBSS run it through the mill). Make sure you're seeing the somewhat powdery white innards of the grains.

Thanks everyone for helping me think through this one!

Let us know how batch #3 goes!

jeremydgreat said:

THE LESSONS:

• 1lb of rice hulls is really a lot. The water will fly right through the grist and quick-moving water means higher chance of channeling. Especially on a tall mash tun. Better to use .5lbs.
• Mix. It. Up. When using different types of grain (kernels, flakes, and hulls) it's really important that it all gets mixed well outside of the mash tun.
• Check the crush yourself (in batch #1 I didn't watch my LHBSS run it through the mill). Make sure you're seeing the somewhat powdery white innards of the grains.

Thanks everyone for helping me think through this one!

Click to expand...

I have never used rice hulls but it does not seem that using more would increase chances of channeling. More may be a waste though.

I don't think that mixing your grains before adding to the mash water would make any difference. When I mill my own I do one type at a time so they are layered and have never had a problem. But, you must stir the mash really well.

I do agree that you need to make sure the crush is good.

THIS is why I love homebrewing. Particularly all grain brewing. There are so many components that you can control about it, but also more things that can go awry if you're not careful. But I love the aspect of figuring it all out. There was a problem and you fixed it and figured out why it happened. I LOVE HOMEBREWING!