Thoughts on target OG

[Gymrat]

Today the OG on my SMaSH came out to 1.046, beersmith predected 1.047. I must have hit all my numbers right.

I have seen a number of threads here and elsewhere where people were commenting that they missed the OG that their brewing software predicted. I have never understood why this would be a mystery to anybody.

Think about it. Your brewing software is basing that prediction on a given efficiency and a given amount of water after the boil. I have no doubt that all of our efficiencys are somewhat different every single time we brew. So that is a given. But how many of us hit 5.5 gallons of water after our boil? I probably did today. Do you really collect the exact amount of wort predicted in beer smith? Then I don't believe boil off is a constant unless you are brewing indoors. Today was a windy day and I had to keep readjusting my regulator to maintain my boil the way I wanted it. There were times when I barely had a boil and other times I was boiling over because the wind I was compensating for died down. That is an extreme example, but temperature, humidity, and a host of other outdoor factors will impact the boil off rate.

So on one brew instead of 5.5 gallons I hit 5 gallons...WOW! my efficiency was over 80%, another time I get 5.75 gallons, crap my efficiency sucked this time, time to do some troubleshooting. See where I am going with this?

Brewing software is an excellent tool but don't expect it to be on the mark with it's predictions when there are so many variables in the brew house.

[Ibasterd]

Today I brewed my first all grain BIAB and missed my og by a bunch. I am not concerned. I am still figuring out the brewing software, brewing equipment and technique. IT will be beer and I will figure it out as I go along or I won't. Like you said "there are so many variables in the brew house." The main one being the brewer!

[FedoraDave]

Good points, Roger.

I actually am more interested in reproducing previous results. I have a number of recipes that I've been making for a couple years now, and if I hit the same numbers next week that I hit two years ago, and a year ago, and six months ago, when I made this same recipe, I'm much happier than when I hit (or come within 0.002) QBrew's projected OG.

[Gymrat]

Good points, Roger.

I actually am more interested in reproducing previous results. I have a number of recipes that I've been making for a couple years now, and if I hit the same numbers next week that I hit two years ago, and a year ago, and six months ago, when I made this same recipe, I'm much happier than when I hit (or come within 0.002) QBrew's projected OG.

That is an incredible accomplishment Dave. Moreso than I think people realize.

[FedoraDave]

Fortunately, I've got my pre-boil volumes dialed in pretty well for my five-gallon AG batches. Still working on the smaller batches, but I'll get there.

I also brew in my kitchen, rather than outdoors, so there's more environmental consistency there, too.

[philm00x]

Like Dave, I'm looking most forward to reproducing results when brewing any given recipe over and over. It is good to aim for what is predicted by the software, but because techniques and ingredients can vary greatly, it is not necessarily accurately representing the product. If you miss the OG consistently by so many points consistently, then your procedure is repeatable and consistent, but you just have to realize your efficiency is lower than stated by the software. In which case, you can just set your efficiency down to what it is saying you're achieving, or you can add extract to recover the points missed. As long as you're repeating your results with negligible variation, and the product that results is something you enjoy drinking and proud of, then don't worry about targets. It's when you have a hard time repeating your results that something in your equipment or technique needs to change.

[John Sand]

I think the point about the relationship between gravity and volume is valid, and some folk miss it. I am not too concerned with consistency at this point. Really just trying to produce the expected results, ie, an ipa instead of a iipa. I'm slowly working on the relationships and volumes, but I tend just to shoot a little low in volume and calculate a top-off. Over time I'm sure I'll get it right down the same way I learned to sail up to a mooring: practice and judgement.

[Inkleg]

Just to throw this out there. I brewed with a really good brewer a few weeks ago. He stated that a good many of his beers had DME added because he missed his OG for one reason or another. He was Georgia Home Brewer of the Year in 2009 and had ribbons lining ALL FOUR WALLS of his brew room.

[mashani]

Just to throw this out there. I brewed with a really good brewer a few weeks ago. He stated that a good many of his beers had DME added because he missed his OG for one reason or another. He was Georgia Home Brewer of the Year in 2009 and had ribbons lining ALL FOUR WALLS of his brew room.

Yeah, I don't really see the point as a homebrewer to freak out if I really feel like I need to add some dme to get up to my target gravity and think having to do so ruined my beer or caused it harm in any way.

More often then not I just don't bother with it at all and roll with whatever I got. It's fine with me because I like variety, I'm not really someone who cares if I make something exactly the same all the time.

If I was a commercial brewer then I'd care more. But I'd also have equipment available to me that would allow this sort of near perfection by controlling every bit of the process more precisely then is possible for me now.

[MadBrewer]

That's some great points and exactly what a lot of brewers fall into. Efficiency goes hand in hand with proper volume measurement. So first off, knowing your preboil volume, evaporation rate and post boil volume are important. Effeciency is just a reference point for brewing calculators and software. This is something that always confused me in Beersmith. Beersmith uses all these variables and factors from your equipment and process to get your numbers, to me this seems to complicate things.

I ran into exactly this brewing the last two times. One batch I ended up with a higher preboil volume from sparging too long which increased my post boil volume (batch size) and lowered my expected SG at 75% efficiency from 1.070 to 1.062. Meanwhile my efficiency didn' change, had I had a 5 gal boil and not 5.5 things would have been fine. To change that I could have boiled down longer or harder to get my expected SG at the end of the boil, but I just let I be.

The last batch, everything went as planned. Hit my numbers, my volumes...etc. Had the correct pre-boil gravity but at the end of the boil I had 1.052 instead of my intended 1.054. No biggie, close enough. Maybe I didn't boil as hard, maybe ambient conditions effected my boil or boil off rate.

I've started to check my gravity with a refractometer and measure my volume during the boil especially close to the end so that I can see if I'm going to be close enough for my comfort. I rather boil down to my intended gravity and lose a tiny amount of wort rather than miss my intended gravity in exchange for my intended volume. The gravity is what will change the character of the beer more so. But when they work out well together, I rather have that.

[Dawg LB Steve]

As an aside from this, yesterday I did my first AG MO/Liberty SMaSH to keep simple for the first. Well all was good until after the boil, had so many other tried to pay attn. to, I ended up with OG .006 under target and was 3.5 Qts short on the volume and then forgot to put water in fridge for top off, so my brew day went beyond long (8 hrs) to get the pitching temp down. Since I pitched the yeast @ 9 last nite, as of 6:30 this am no bubble action yet out of the bucket, would I be able to boil up some DME and get in in the bucket to get my OG and volume up to 5 Gallons? Or is it too late ( If I could it wouldn't be until about 6 tonite )?

[Brewbirds]

I ended up with OG .006 under target and was 3.5 Qts short on the volume

I may not be reading this right but it doesn't seem like your OG should be that low if you were also low on volume.

Can you give some more info on this brew please, i.e. gravity readings and volume intended?

Also before adding to the bucket and risking oxidation or infection have you put your final numbers in your software to see how this batch would end up as is?

[John Sand]

Steve, while many would advise you to leave it alone, I've had good success with adjusting gravity and IBUs in the fermenter. Adding hops, sugar or fruit is standard while fermenting, no harm in adding LME or DME. Just calculate your extra water and gravity.

As for the rest of the discussion, I check my gravity with a hydrometer as I go along. Scoop some out as I begin the boil, it cools to readable temps before the boil ends. Take another sample while chilling. It all works out.

[Dawg LB Steve]

I used QBrew and calculated out to 1.046 and 5 gallons, as I topped of I kept checking the SG ( add water, stir the crap out of it making sure it was mixed). I also checked SG before the boil I had 1.046 (used 8 Lbs Maris Otter), started the boil with 4 gallons between the mash and sparge. I got to just a bit over the 4 Gal. marks and had SG reading of 1.040 that is where I stopped. As I said it would not even be 24 hrs in and don't know if the yeast (US05) took off yet as I'm at work, but as of 6:30 this morning it hadn't started bubbling yet.

[Kealia]

When I design a recipe or am working to clone/brew somebody else's recipe I do aim to hit the target OG so I have the beer I intended. If I'm a few points short, I roll with it. If I were to come up REALLY short I would make any adjustments with DME/LME so that I was nearer to it. I don't brew near as much as some on here so when I do it's "purposeful" in the sense that I do want the end product to be what I intended it to be. That way, I know I can make adjustments next time around to make it better/change something.

But like I said, a few points here or there don't keep me up at night.