Measuring the mysterious OG?

Discussion in 'Beginners Brewing Forum' started by Browmore5, Mar 7, 2019.

  1. Browmore5

    Browmore5 New Member

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    So as beginners we read about all these numbers and try our best to make sense of them. I've made four batches so far and have enjoyed everyone, except the one I just bottled today but in a few weeks I'm sure I will be enjoying that one. I was chasing the OG on the first 3 batches and never got really close - using a Mash&Boil (no pumping) with all grain recipes. (My understanding that the real OG is based on the amount/kind of grain used when brewed under specific conditions, so it's more a goal than a must hit number) After reading around in the forums, I figured the recipe kits I was getting were not milled fine enough, which I might try going finer next batch. Thinking about the process though, on my last batch I stirred a little more vigorously, mash a little longer and took a gravity sample right after the mash time was up (before sparge). It was right on within a point or two! Then I sparged, following the instructions in the M&B, Palmer, and BF with 170 water to get my volume up to were it should be and took another gravity reading, This is where I took all previous readings on the earlier batches. This time it was just like all the others about 20-5 points low? More thinking and a walk i in the woods --- Not really surprised since water's gravity is 1. Adding sparge water over the grain would bring it down although I thought it's purpose is to pull the remaining sugars out? Can someone shed some light on this? I thinking maybe not to sparge, or use less, and/or just use more strike water at the start? I know the answer is to just have another great homebrew, but open to your thoughts...
     
  2. jmcnamara

    jmcnamara Well-Known Member

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    Boiling would concentrate the sugars, so at first read it would make sense that gravity is lower. Unless I'm misunderstanding
    But I just got done happy hour so no guarantee of my reading comprehension
     
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  3. J A

    J A Well-Known Member

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    OG is the gravity of the entire volume of boiled wort before fermentation. Any other gravity reading before it's cooled and ready to hit the fermenter is supplemental to that. It's good to know pre-boil gravity, and even to get a gravity reading before sparge but those are not the OG number and can all but be ignored.
     
  4. Nosybear

    Nosybear Well-Known Member

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    First, you're right, the OG numbers are a target. I generally hit within +/-0.003, anything outside of those boundaries I adjust, either with dechlorinated boiled water or DME. The recipe gives you a preboil target as well, generally lower since you're concentrating the wort. The OG is the important one, as JA says. Beer is made from agricultural ingredients so some variation in yield is to be expected. I use the same system you do, a passive mash tun and batch sparging, no recirculation. If you're measuring the OG, the gravity after the boil, and missing by 20 points, something is wrong with your instrument, not the wort. In general, I find if I hit the preboil gravity, I hit the OG.
     
  5. J A

    J A Well-Known Member

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    Poster seems to be confusing OG with pre-boil gravity. I get a lot of boil off so my gravity's over 10 points lower when measured at pre-boil than it is when measured for actual OG going into the fermenter. If he's measuring pre-boil, there's no way he'd be hitting target OG.
     
  6. Mark Farrall

    Mark Farrall Well-Known Member

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    Sorry if there are bits where I may be labouring the points you already now, but I hope that's better than not...

    At the start OG may be more of a target that you would ideally like to hit, but it's not the end of the world if you don't. My first few batches I didn't even have the equipment to tell if I did hit it. But, as you get more experience you start to know your strengths and weaknesses when it comes to putting a certain amount of sugar into a fermenter (basically what OG represents).

    With that knowledge comes the ability to adjust the recipe, mash times and temperatures and the amount of water you use so that you can hit that OG more often than not. And then missing it means more that it probably should (as the amount of swearing that happens when I get low readings after finishing the mash would show). So if you're asking questions about how to get closer to OG then you've started that journey.

    Probably some of the first things to do are break OG down into a smaller steps. This lets you see which of the steps on the way to OG are the ones causing you the most trouble. Some of the posters above have mentioned boil gravity. Getting a measurement of the sugar at the end of the mash phase is great for working out if your problem is really in the mash phase, as it generally is. So if you get a measurement of the gravity before the boil we can all ignore the hop absorption and kettle dead space issues that are more about filling in your equipment profile correctly.

    So I'm taking it that most of your questions are about getting the right amount of sugar into the kettle before you turn on the heat...

    As you're using a single vessel with a basket, milling finer may help, but go too far and pulling that basket out will end up taking more out than you hoped to gain.

    Again, stirring will help but it's probably one of the smaller gains you can make. And as you've got temp control during the mash in your system it shouldn't actually cause any problems. Just make sure you are keeping the temperature consistent.

    On the sparging issue. Sparging will always cause the gravity of the collected wort to drop. The sparge step is nearly always talked about as getting sugar out of the grains, but I think of it as diluting the wort to hit the starting volume for the boil, while grabbing some extra sugar from the grains.

    So when you took your reading that showed that your gravity was right prior to the sparge you had two choices. Skip the sparge and make a smaller batch or add the sparge water and get a lower OG. Virtually none of the resources you read will talk about it that way as everyone knows their systems well and has a track record of getting the right gravity prior to the sparge (and they want that 5 gallon keg filled at the end of the brew).

    So I find that the most important thing to focus on first is making sure you're at the right temperature for the right amount of time. You can also add more time. It will help you out if you're roughly in the ball park on temperature. It won't help you out if you're not.

    The next one is pH. That's probably one to leave for a little while if you can. If not we'll need to know things about your water profile the recipe your using (or the kit makeup) and that puts out outside the standard beginner conversations. Happy to do it if you want. And again more time may help you out if your pH is roughly there, but won't help you out if you're nowhere near.

    And there won't be one answer to fixing the problem. It'll be many steps. For some brewers it's a long journey that they never finish, for most of us we get it to a point where it's good enough and we accept that more gains aren't worth the effort.

    Better to cut it off here as it's probably gone too long already. Hope it helps.
     
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  7. Head First

    Head First Well-Known Member

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    I am surprised @Nosybear didn't suggest it yet but as a new brewer the best thing you could do for piece of mind and great experience would be pick out 1 recipe and brew it several times making sure to make precise measurements each time. Look for consistency, and when that is achieved you can consider changing recipe to get the OG (Measurement of sugars in cooled wort after the boil before fermentation.) you are shooting for. Small water volume measurement can change your readings quite a bit especially if you are making small batches. If you like the beers you are making then you are already ahead of the game so sounds like you need to work on and understand your process a little bit better. CHEERS!
     
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  8. J A

    J A Well-Known Member

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    All the helpful info about increasing efficiency to achieve target OG is great but misses the point that the OP seems not to be taking an actual OG reading and instead is basing his measurements on pre-boil gravity reading. Of course it's low...no amount of tweaking the process will give you your target OG before you boil down the wort to the proper volume.
     
  9. Nosybear

    Nosybear Well-Known Member

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    Didn't seem to be a popular suggestion....
     
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  10. Head First

    Head First Well-Known Member

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    Al new brewers want to jump right in and exbeeriment but most will eventually do this (myself included) and be better brewers for it. I vividly remember my improvements with this in mind. And I might add I did switch it up but would repeat a pale ale with good notes while trying other recipes in between. Good notes and good measurements make good beer consistently.

    Agreed, that's why I noted when to get a correct OG.
     
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  11. sbaclimber

    sbaclimber Well-Known Member

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    I am so glad I never bothered with any gravity measurements pre-OG :D
    Basically I did what Head First mentioned....brewed the same recipe enough times to be able to accurately enter my losses (head-space, boil-off, etc) and brewhouse efficiency into the calculator, and now hit my OG (+-) every time. Obviously a thicker or thinner mash or other malt will change the overall efficiency, but that is just a matter of tweeking that number a bit to fit the recipe. Consistency is the key...
    @the OP, imo, as J A said, one only needs the pre-fermentation OG. ;)
     
  12. Nosybear

    Nosybear Well-Known Member

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    I think it comes down to craftsmanship: A good craftsman knows when he can "fudge" and make it up later. Pre-boil gravity is one of those areas where if you're close - up to each individual brewer to define "close" in this context - you're fine. Again at post boil, the OG should be close. I usually adjust a "miss" of 0.002 points either way. As you get to know your system, misses greater than this will be rare (and usually in odd situations like high-gravity beer).
     
  13. Group W

    Group W Well-Known Member

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    You are getting good feedback here. It takes a while to learn the brewing lingo. It was confusing to me as well starting out. “Four batches,” hell, it took me at least 15 batches before I started piecing the all grain puzzle together. Keep studying and brew often. Cheers!
     
  14. Browmore5

    Browmore5 New Member

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    Thanks again everyone for all the great feedback. I am learning alot and it's nice to know I can ask, even if without in-depth knowledge and get such good understandable answers. I do take readings after boil, and again after cool down and aeration. So, this early reading was more out of curiosity than worry about numbers, and since I could put in back into boil it's an easy one to grab. My after boil and after aeration numbers on my first two batches were not much different than the pre-boil numbers which to me seemed impossible so I didn't even bring it up, but it did happen more than once (and it another discussion that seems to have had plenty to read about). I took the pre-sparge reading just to see how I was doing on my mash process and will probably do that again. I think the extra stirring and longer mash is a good addition to my process. I'm leaving the electric controls on the M&B to worry about keeping the temp where it should be. I did take mast measurements with a thermometer on the first few batches and it seems like it's doing a good job and that's why I went in this system to begin with. I read about adding a pump, but didn't really want to go there, and now, don't think it's needed.

    Because I split the 5g recipe batches in half, I have done each recipe twice ...well, almost - the 2.5 g batch didn't last very long so when I order my second kit I added some base grains and extended the recipe slightly to 3 gal. With a little speciality grain, (it's why I knew all-grain was the way to go), the beers and OGs are very similar so it's almost as @JA and others have discussed ...which really good advice but I can see how it's not readily followed. ..just too many options to try. But I will be brewing these again, just might not be next.

    Good notes and good measmts = agree, agree!! ...and I do need to get better with my notes. I also know I need to tweek my numbers in the brew house - I mostly guessed or defaulted when first inputting. I'm surprised how little is left behind on the transfers (not so on my first batch, but getting better each time). I will be continually working those numbers as I understand my process.

    I hope to be laughing at this by the 15 batch @Group W , but that will be in years of ever better beer drinking. Thanks again to everyone for the friendly advice, hope those reading along also had some questions answered. My only wish is the search worked better because I'm sure I'm not the first to ask but really couldn't find a way to search that came back with something helpful - at least not as helpful as you all have been.
     
  15. Craigerrr

    Craigerrr Well-Known Member

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    Embrace the learning process. Keep posting and asking questions, the experienced folks here are happy to help. I have benefited immeasurably from the help and advice on Brewers Friend, but you can't learn it all at once.
    Welcome to the hobby (obsession)!
     
  16. ChicoBrewer

    ChicoBrewer Well-Known Member

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    I have made the same pale ale at least ten times and boy have I learned a lot. Tweaking process makes a brewer.
     
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