help me care about gravity readings

If your beers are turning out the way you like them, there's really no need for gravity readings, IMO. I try to do it consistently, if only to help me detect problems that may creep into my process. It also helps me describe some of the technical aspects of the beer when discussing it with other brewers.

 

Obviously.

For one thing, if your beer is not turning out the way you want/expect subjectively (e.g. mouthfeel, or alcohol strength), these numbers can help you diagnose the problem.

For another, if you want to design a new beer recipe, it's helpful to have data about how your system/process/ingredients perform (mash efficiency, attenuation, etc.) so you will know what to expect from the recipe you are building.

 

Generally, OG is just a measurement, to see where you are starting from.
Of course, it can also sometimes indicate a problem, if you are WAY off of what is expected; I.E. 20lbs of grain in a 5 gallon batch and your OG is 1.050. Or 10lbs giving 1.100.
FG is a bit more important, in that it tells you when your beer is done, if that number doesn't move for a few days.
Again, it can indicate problems if you are much higher or lower than expected, indicating bad / stalled yeast, or an infection.

 

To me, the importance of taking the final gravity reading(s) is to decide for certain when the fermentation is complete so that I can safely bottle it without concern for continued fermentation once in the bottle, thus having bottle bombs. Knowing the OG and FG and also nice to know to be able to calculate the ABV of the beer.

 

Gravity readings are essentially data points that you can use to evaluate a huge portion of your brewing process, adjust your product, brew to style, and improve your ability to reproduce good batches / improve consistency.

 

I care mostly about gravity readings to determine how fermentation is going. If I'm not getting complete attenuation then my beer is going to suffer. If I'm not taking gravity readings, I won't know. My beer won't be the best it could be and I wouldn't have an idea on how to fix it.

 

Some more detailed feedback for you.... Not my most poignant outline (just woke up and had a good night at my brew clubs monthly meeting yesterday):

preboil gravity: (combined with preboil volume)
- can tell you how much sugar you have extracted from your grain which helps you judge the efficiency of your mashing / lautering process, sends up a red flag (when low) that points you in the direction of what to focus on for improving it, and (when consistent) helps you create future recipes so that you are more likely to execute your beer as designed / intended.

original gravity: (combined with postboil volume)
- can tell you more about your boil off rate and, most importantly, acts as a baseline measurement that will later tell you how well your yeast fermented your beer and how much alcohol is in your final product (when compared to final gravity)

specific gravity readings during fermentation:
- can be used to judge the rate of fermentation which can be an indicator of yeast health, whether your pitch rate is proper, whether your fermentation temperature profile needs to be adjusted, can also help you really understand the different behaviors and preferences of various strains of yeast you choose to ferment with.

final gravity:
- needed to determine how well your yeast attenuated your batch, can serve as a general benchmark for the sweetness vs. dryness of your beer (although perception can be different), can be used in decisions to increase, decrease, or keep your mash temperature the same next time you repeat the batch, can be used to determine that fermentation is actually complete which helps you avoid bottling too early and having your bottles explode, etc.

 

"I guess I'd just like to appreciate this information more, instead of it being just 'data' that telling me if my beer's fucked up."

What's more to appreciate? It's just a number representing density compared to water, but one that beer nerds like to toss around liberally when they're in the company of normal people

 

To piggy back on what others have said... what happens when you start opening bottles a few weeks in and they spray foam all over your kitchen or start exploding in the cases? If you know what the FG of the beer was at bottling you can save whatever is left from the geysers and take a reading of it. Is the FG the same? Then you added way too much priming sugar. Is it lower? How much lower? Could be you bottled early and the yeast wasn't done. This is why the OG is important, the difference between the two readings and a little math will tell you the degree of attenuation. If the yeast is known for steady 75% attenuation (eats 75% of the sugars) and your pre-bottle FG shows it has stopped at 65%, but now is at 70%, it is possible that the gushers are from the yeast finishing the job in the bottle instead of the bucket. If the yeast was in range of the normal attenuation, say 76% but you have major geysers, then you taste the beer, is it odd? phenolic? sour? funky? A whole new world of possibilities open up like is it just your bottling bucket that is infected? the bottles? the fermenter? racking cane? Without the OG and FG there isn't really a way to know what is going on except, oh man, this beer sucks, let's make a new one and scrap this. If it is an infection in the brewery it will make a lot more of your beers suck (trust me, I know, lost 6 in a row before I even realized the problem).

 

I like Mike's post of: "If your beers are turning out the way you like them, there's really no need for gravity readings, IMO."

Having copied what Mike stated, permit me to bring up the discussion topic of beer recipe design. When it comes to formulating a new recipe the metrics of OG and FG are fairly important. You need to make decisions like:

• How big do I want my beer to be? In other words what OG do I want to achieve a target alcohol amount?
• How much mouthfeel do I want with this beer? In other words, what FG should I shoot for?
• etc.

By measuring the OG and FG of your beers you get to know how close you achieved on what you designed via your recipe.

The past few years I have been attempting to tailor my beers to have a bit more mouthfeel since I think this quality can enhance certain beer styles. I modify my recipes to achieve a bit higher FG (e.g., a FG of 1.014-1.015 for a moderate gravity beer) and I take my gravity readings to confirm that I am meeting my recipe targets.

But, if your beers are turning out the way you like them there's really no need for gravity readings.

Cheers!

 

I suppose you can continue brewing with a "I don't need to know how to build a chair to sit in one" kind of philosophy, but determining OG and FG seem to be pretty essential, imo. If you're taking the time to brew it seems nutty to avoid OG/FG readings.

For all of the elements involved in homebrewing that may seem too complex/advanced right now (ex: pH, yeast starters) there are few things easier than taking gravity readings (assuming you have a hydrometer). Those readings tell you where you're starting and more importantly when your beer is done - and ready to bottle/keg (in addition to giving you the ABV).

 

If nothing else, then at least this...

 

There are lots of reasons to take gravity readings, lots of them already mentioned.

But the most common questions I get from other people drinking my homebrew are, "What kind of beer is it?" and "What's the alcohol percentage?"

Can't give an answer to the 2nd one without those gravity readings. I suppose you could guess and be fairly close as long as your efficiency is dialed in (but you wouldn't know if it were without gravity readings) and no variables ever affect that efficiency (i.e., a bad crush).

 

You also may not be able to provide an answer to the first question without having an answer the second since ABV is a factor in style determination.

 

I have a friend who never does it and I like 90% of his beers.
On that note I always do it, for the reason of knowing the ABV, and to track efficiency at which I have been hitting between 79-82%.
So if you don't care don't do it.

 

abv obviously and its nice to see what % of residual sugars are present in regards to body. also adjusting your og to fully attenuate your batch.

 

I will say I don't bother to take OG on extract beers. Assuming OP has only brewed one beer he is most likely doing extract and the FG might be the only relevant piece of information in his case.

 

Yeah probably wouldn't need to measure OG if his volumes are perfect, but he would still need to know it, based on recipe details or whatever.