How important is getting gravity readings?

If you bottle, bypassing gravity readings can result in a bottle exploding in your face. So there's that.

Let's see here...checking beer gravity versus risking losing an eye...hmmm.

It's a tough call, but I'm going with check starting and finishing gravity. Always.

 

checking your gravity has two main purposes. one, it lets you know alcohol content. two, it lets you know when fermentation is complete. that is pretty much it.

one is nice to know, but really not all that important. if you have a good handle on style and recipes it is just confirmation.

two is very important if you are on a schedule or if you are not sure of your fermentation routine. i have made hundreds of brews over the last two decades and rarely bother to get an FG. i do like to get my OG when i remember, mostly to check efficiency. but fermentation is complete when it is complete.

so, the answer to the questions is simple. getting gravity readings is important if you need the data. but if you are a decent and consistent brewer is it not essential to get this data.

edit- until you blow up some bottles like BB mentioned. then yeah. you better be confident in your ability to know when the yeast is done and not just stuck.

 

I agree with billandsuz . The main reason for OG is just knowing how well you did on the Mash extraction and if your practice is repeatable and efficient. The FG is not as important IMHO but again gives you clues to the Fermentation progress and attenuation (which varies with both yeast type and percentage of non-fermentable sugars). FG is not a reliable indicator of fermentation completion so don't count on it as a "safe to bottle" marker. For the time it takes, to I always read gravity and wort temperature and jot it down in the margin for future reference.

 

Damn the glass shards...full speed ahead! : )

 

Pick up a refractometer and you'll only need a ml or two to check gravity. Problem solved.

 

So you would rather not waste beer by checking to see if it is ready? Well, by all means, plow ahead and package 5 gallons without checking to see if it is ready. The risk is that the beer might not be at final gravity. Because you don't have a hydro sample to taste, you may let a few cases of diacetyl and acetaldehyde get past you. Seems like you are being penny wise and pound foolish.

Use a hydrometer, taste the sample. Package when it is ready.

 

So long as you pitch healthy yeast, have fresh ingredients, and regulate fermentation temperature, beers generally come out really good. If it applies, you need to hit mash temps too.

I take gravity gravity readings for starter wort, usually. On brewday the refractometer generally stays in its case. I brew to drink and share with friends. It would be more important if I were trying to recreate something or win a medal. I don't bottle either, which lets me not worry as much about FG. I'm not condoning anything above, it's just the way I do it.

 

I check the OG and FG on new brews I haven't done before. On my tried and true regular brews I rarely check. On most of my high gravity beers I usually just check the FG to make sure it's done. I just don't feel the need to know the exact #'s of beers that are for me.

 

I used to not worry about IG and FG, but I've matured as a brewer (snicker...) and have found more advantages that I can count for recording and taking gravity readings. Lets just say, you don't have to, but it's a really super good idea. (You'll make like 7 batches of beer that turn out good while not taking gravity readings using kit beers then suddenly.... BAM! your wife/gf runs off with the pool man, your dog runs away, your car runs away, you lose your house... but worse, gallons of beer are bad.)

For the love of all that is good and holy (or heck, just the love of beer) learn how to, and start taking gravity readings.
This message brought to you by... bob! (get it... because the... little floaty thingy bobs up and down in the .... beer)

 

I tend to forget to take a FG reading, but I keg and I very rarely package the beer before 3 weeks and never before 2 weeks. I also tend to do a lot of similar beers (APA/IPA and saisons) so I don't worry about stuck fermentations.

TL;DR I am lazy and any problems with my beer are not attributable to not taking a FG reading

 

There are calculators to correct for the alcohol, but you are correct that you won't get a true FG reading

 

The SG scale on your Refractometer (probably on the right side, if there is one) is useless for FG, mainly because of alcohol. But it's also bad for OG, because it is for a single sugar type, which is not what wort contains.

The Brix reading, however, is very useful for both OG and FG. But you need a good calculator to get a good estimate of OG and FG out of it.

 

http://www.beeradvocate.com/community/threads/help-me-care-about-gravity-readings.204599/
http://www.beeradvocate.com/community/threads/specific-gravity.233459/


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.

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 usually don't bother with OG readings, just something to get paranoid about. My beers taste good and generally have the desired effect after a couple. I ferment in a bucket and drip a sanitized hydrometer in the bucket after the krausen has dropped. I'll note the reading and keep an eye on it for a few days to note when the ferment's complete. If the FG's not pretty close to what I want I might use the data to decide about raising the temp a bit, stirring it up, etc., or adding a yeast kicker it it's really stuck.

 

I think it's very important. I once kegged a brew that hadn't finished when the other beers from that batch did (used different yeasts). Went to pour a glass, and was extremely disappointed. If I had checked prior to kegging, I could have re-pitched, and kegged one of the finished beers. Instead I had five gallons of crap!

Even if you've had 20+ batches that were great, and had no problems finishing out, don't trust that everything is always going to be that way. How do you know how viable your yeast is? Do you have a controlled fermentation environment? What if your thermometer malfunctioned during your mash, and your temp was too high, leading to lots of complex sugars that won't ferment, resulting in a high FG? There's ways to address that if you check before kegging/bottling.

I would always recommend checking at least FG.

Cheers!