What makes OG?

[DuffsNut]

I have just put my second batch in the fermenter...it was an Oktoberfest from True Brew. The directions very, very poor (surprise, surprise). Anyway, the directions specified an estimated OG of 1.042 - 1.044 and ended up with an actual OG of 1.054. I didn't follow the directions in several ways including adding the freshened at different times than specified and brewing the batch for 65 minutes instead of 20-30 minutes like it said. I choose to think of this as an improvement and me using my intuition as a growing brewer. My real question is: what affects the OG? My second question is how would this affect my batch and/or should I be concerned about this variation?

 

[Manoau2002]

The amount of sugar or malt extract added to your brew

 

[iron_city_ap]

There are lots of things that affect your gravity. Essentially, its just a measurement of the density of your beer. For example, if you boiled for 65 minutes instead of 20-30, your wort will be more dense and have a higher gravity reading. As the wort ferments into beer the gravity reading becomes lower because alchohol is less dense than water.

Did you do a full boil or a partial boil? How much wort did you end up with? Was it more or less than what you expected? Did you top off, and if so, how much water did you add? Like I said before, there are LOTS of factors. I wouldn't be worried about the higher OG. All it means is that you have more fermentables in your beer. Your beer will probably be slightly more 'malty' and will have a higher ABV. Nothing to worry about at all.

 

[l1ranger]

Water has an SG of 1.0000 - assuming good ole pure water.
everything that gets dissolved into that water makes it more dense, increasing the SG. The more that is dissolved, the higher the SG goes.
This could be lots of stuff, but in your case its the malt extract - if you boiled off water and didnt replace it, your OG would be higher. If you did replace but didnt get it all mixed well, you got a false reading that is higher than what is should have been.

In the end, with extract, if you got the right amount of water and the right amount of extract - you're OG is where it should be

 

[DuffsNut]

Thanks everyone! Since I did not follow the directions, I assumed that could be the variation in the OG.

Iron City: I did do a partial boil. I started with 3 gallons of water and ended up with a little bit over two gallons. I added 2 gallons of water and ended up just over 4. Since I was trying for 5 gallons, I added another almost gallon to bring it up to the 5 gallon mark on my fermenting bucket.

My first batch I started with the full five gallons to boil and ended up around 4. The biggest difference with the lower amount of starting water was it was easier to prevent boil-overs. I had zero with this second batch which made cleanup easier.

Thanks again!

 

[Revvy]

Even though you say that you didn't stay strickly with the recipe, one thing to realize is the it is hard to miss your OG in an extract batch, and in reality you more than likely DIDN'T.....It's just that it is USUALLY difficult for the original gravity to actually REFLECT this fact.

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.

So even if you have a set kit and add 2 pounds of dme, or used more or less water, you can use brewing software to figure out what you gravity should (and is actually) at. Just make the appropriate changes to the saoftware and it will show you.

 

[Chad]

While the instructions that come with most kits are indeed deplorable, they mainly fail by telling you to remove the beer from the yeast way too early. Most at least get the amount of water to extract about right. As you discovered, OG is the ratio of dissolved sugars to volume of water. Boil off more water and the concentration of sugars goes up.

When did you take your OG reading? You say you added 2 gallons after the boil and then added another gallon to the fermentation bucket, bringing you up to 5 gallons. I'd be willing to be you took your reading before adding that last gallon. (ETA: or as Revvy said above, you didn't mix thoroughly). If you got the correct amount of wort, you almost certainly got the specified OG. Extract is pretty consistent. The sugars don't go anywhere, they just get diluted more or less.

John Palmer's How to Brew is free online, at least the 1st edition. Some of the information on fermentation times is a little dated, but the instructions and explanations for how to do an extract brew, extract+steeping grains, partial mash, and all grain are still an excellent starting point. Your brewing will improve dramatically.