How important is checking OG?

Assuming the volumes of extracts, water, and steeping grains is correct, is it safe to assume that the OG will be what the recipe or recipe calculator says it should be, or at least pretty close?

You will see a lot of threads on here about people missing OG, whether coming up short or going over.

Having said that, I'd say you should be checking your OG.

With an extract kit you will be very close to what the kit says if you use all the ingredients and end up with the proper volume.

As far as the need to know the OG. With all grain it will tell you if you converted the sugars at the expected rate. Then you can take steps to correct things if your OG is off.

Other than that the only real reason would be if you wanted to calculate the ABV.

Checking OG is not necessary to have an outcome of "beer". All things considered you can brew as much beer as you want, having never checked OG, and still make great beer.

Checking OG is worth it for many reasons. Simply checking to see if your anticipated OG is what the true OG comes out to makes it worthwhile. If you have a problem with your brewing process, the OG will reflect that. Ultimately its something that will help a brewer create the best beer they can.

If you have a tool that can help you do something better, why wouldn't you use it?

I rarely check my OG. I partial mash, and check the gravity of the mash, but for the rest, I just calculate it for the most part.

I might check about 1 in 20 batches to make sure everything is OK, and I always find I get what I'm supposed to get.

I see so many threads where they have the wrong gravity, that unless you really mix everything up, you are going to get an incorrect reading. You may think you have everything mixed well, but from the number of threads about it, I would say it is harder than you think to get everything mixed.

+1 Just check it bro!

It's not really NEEDED to check OG, however, it's part of getting better at your process. With extract batches, yeah, there's really not a point because if you do everything correctly the OG will be right (and top off and wort not mixing can make you think you did something wrong when you didn't).

However, knowing the OG becomes a little more useful with all grain, since it's not fixed like it is with extract, and changes depending upon mash efficiency (and boiloff rate, but that applies to extract too if you're doing full boils). And if you have any dream of being a competent brewer able to brew consistently, that's one of the first things you want to dial in for a predictable outcome.

Gravity readings help us learn from our own mistakes, take the time to do it

Probably a good habit to get into.

For extract........ I would say it does not matter at all. You will get the gravity you are supposed to get if you end up with the calculated volume of the recipe at the end.

However, if you transition to all-grain it becomes more important to make sure your getting decent efficiency and to have a chance of consistently replicating beer.

So - getting into the habit early is probably a good idea, even if it is not a real necessity at this point.

*One thing a lot of beginning brewers do though is they add top-off water at the end to get up to 5 gallons. They don't mix thoroughly enough and their gravity check seems all out of whack (even though it is fine). If you do use top off water - realize that it can stratify and give you a weird reading - even though everything is just fine.

Getting in the habit of checking OG is a good practice.

However, doing extract it is nearly impossible to miss your OG if the water volumes are correct.

If you progress to partial mash or all grain then, yes checking OG is more important.

Honestly, if you measure your OG and it is off of the projected OG by more than a point of 2, then you measured something wrong - either the water or the extract or the gravity reading. Those are your only options.

Since measuring gravity is pretty easy, I'd keep doing it. If nothing else, it provides another check to make sure you haven't forgotten anything. eg the gravity is too high - better check to make sure I added enough water.

I always take an OG reading on everything,whether PM or AE. If you make your own recipes,even with AE,you'll want to know your OG for consistency's sake. Even with kits,I prefer to check,since other process variables can come into play with the boil,etc.