Testing Specific Gravity.. Useless?

I understand that testing specific gravity, for % attenuation, with a hydrometer can indicate when to rack beer from a primary to a secondary.
However, if you condition in the primary why test the specific gravity?

I also understand that if you are mashing your own malt, you will probably want to test the specific gravity in order to refine your mashing technique. But, what about brewing from malt extract or malt extract + specialty grains?

Even if you leave it in primary for a month, its still a good idea to check the gravity. If something does go wrong and you dont know if its fermenting or not, then the first place to check and the only place you can accurately see if its fermenting is with a sg reading.

It's also to check and see if you get a stuck fermentation.

c1377,

As an example, my first brew was a stout that a friend and I did on 6/11/08. After 3 weeks in the primary, the SG was 1.020! For most beers, it would seem to be done in that time frame. Even now it is still giving indications of fermenting!

Hopefully tonight it will be done, barring a higher SG than the predicted final gravity. I do not want to clean up a stout bottle bomb

Numbers are a great way to assure oneself of doing the right thing

I never used my hydrometer much wen I did extract. (seemed too much of a hassle). I just poured the wort into the fermentor and transfered to the secondary about a week later and kegged it about 2 weeks after that.

Now that I am doing all grain I use it all the time though.

I agree with special hops, I stopped using a hydrometer after I broke my second one in my first 4 batches. I only started using one later, when I switched to Partial mash. and even now, I don't use it to decide when to rack or bottle, I always rack after one week and bottle after another two weeks. but as long as I'm taking a sample at racking, I might as well take an SG, just for curiosity.

honestly since those first few batches I don't worry about when to rack / stuck fermentations, etc. a week in primary should be plenty, and if there's still airlock activity you can always wait another week before racking. And if you're pitching the yeast into well aerated wort and fermenting in the right temperature, you're not going to get a stuck fermentation.

So you guys don't care about your numbers? This seems crazy to me, but I guess if all you want is beer and you don't have people asking you questions like, "what percentage is this?" then it doesn't matter. I live with beer drinkers, I have a homebrewing next door neighbor... All this stuff seems pretty damn important to me.

Aside from the fact that it is good to know you've hit an acceptable gravity. If I racked a saison at 1.020 because I just assumed it was done, I'd kick myself.

I measure now that I have gone all grain. But with extract you pretty much know how much sugar you've got in there.

Man, Its like bad information thread in here.. People saying hydrometers dont need to be used, One week is enough. Wow.

I had a batch that stopped with almost all airlock activity in one week. So I took a reading, FG was supposed to be 1.012, the reading was at 1.022, had I bottled then I would of lost the whole batch to bombs. I waited another 1 1/2 weeks and it finished up right at 1.012. Use a hydrometer. Your beer with thankyou and you wont have to clean up 2 cases of bottle bombs!

Work smarter not harder!

carnevoodoo said:

So you guys don't care about your numbers? This seems crazy to me, but I guess if all you want is beer and you don't have people asking you questions like, "what percentage is this?" then it doesn't matter. I live with beer drinkers, I have a homebrewing next door neighbor... All this stuff seems pretty damn important to me.

Aside from the fact that it is good to know you've hit an acceptable gravity. If I racked a saison at 1.020 because I just assumed it was done, I'd kick myself.

Click to expand...

I generally know what percentage it's going to be based on the OG and the expected FG, roughly speaking that is.

Good beer is in the eye of the beholder, and I find that I don't need to follow the #'s or any other guidelines to make what I consider to be good beer. And I've never had a bottle bomb yet.

I measure SG the first time a day or so after the krausen falls, just to make sure I don't have a stuck fermentation. After a week the SG is usually within 2-3 points of my target gravity. I'll measure again a few weeks later, before bottling, just to see where it finished off. I keep records of ABV and attenuation in my notes.

Arneba28 said:

Man, Its like bad information thread in here.. People saying hydrometers dont need to be used, One week is enough. Wow.

I had a batch that stopped with almost all airlock activity in one week. So I took a reading, FG was supposed to be 1.012, the reading was at 1.022, had I bottled then I would of lost the whole batch to bombs. I waited another 1 1/2 weeks and it finished up right at 1.012. Use a hydrometer. Your beer with thankyou and you wont have to clean up 2 cases of bottle bombs!

Work smarter not harder!

Click to expand...

I never said it was better not to use one. Just that when I was doing extract I was lazy and didn't.

Thanks for your comments.
...let me try to ask my Q again.

(1)
Does conditioning change the Specific Gravity?


(2)
How can I know when conditioning is finished?

Is the length of Conditioning proportional/inversely proportional to the length of the attenuation phase?
Can I graph the Specific Gravity, to come up with a half-life for each batches yeast concentration,
and thus extrapolate the conditioning curve?

OR
(3)
Can I just forget about using a hydrometer?

I would much rather leave my batch un-touched for 3-4 weeks in the primary, and then bottle.
Can't I just estimate % continuation by monitoring the clarity of the brew?

c1377 said:

Thanks for your comments.

Here is what I want to know:
(1)
Does conditioning change the Specific Gravity?


(2)
If conditioning can not be tested by Specific Gravity, how can I know when conditioning is finished?

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1- no, conditioning doesn't change the SG. The only thing that would change the SG is fermentation, or adding more sugars.

2. Conditioning is a subjective term. All beers seem to improve with age, and then after a period of time, will no longer improve and indeed will start to decline. Generally, "big" beers will continue to improve for a while, since it needs the conditioning time. A barleywine might be best in a year or two. Highly hopped beers will start to lose some hops aroma after a few months, and some beers (like hefes and other wheat beers) will also be past their prime. Now, that time isn't written in stone at all. With proper ingredients, most regular beers are great for about 6 months.

c1377 said:

(3)
Can I just forget about using a hydrometer?

I would much rather leave my batch un-touched for 3-4 weeks in the primary, and then bottle.
Can't I just estimate % continuation by monitoring the clarity of the brew?

Click to expand...

Clarity is not going to give you any sort of estimation whatsoever. You can just leave it for a while and hope for the best, but really taking a hydrometer sample isn't all that difficult and you won't f anything up by doing so.

I guess I am just saying that using a hydrometer is best practice. If you want to do it right and you want to understand the outcomes of what your yeast has done for you, then it is best to record this stuff. If you came back to a beer after a couple of weeks in the bottle and it was a big mess of diacetyl because it wasn't done cleaning itself up and you bottled too early, you'd probably be upset.

But then again, that one guy only ferments for a week and he likes his beer so I guess it doesn't matter.

I check my initial and my final. Initial to see what yield I got off the grain (usually 85%), and final to know how much I can drink and still make it to work the next day.

As far as knowing when to rack, I've got coworkers who will religiously check every day after a week and only rack if the SG has changed less than .001; I'm an atheist and just wing it based upon experience.

Generally if the SG was less than 1.050 I find 7-10 days in the primary is sufficient, and if it is higher I'll give it 14-20 days.
Depends on patience and motivation.

My coworkers brew in buckets and carbs with valves, so it is much easier for them to just dispense into the jar and read the SG, I've got technical difficulties that make it more cumbersome and less sanitary to do such checks.

I'm happy with my brew, and if it ain't broke don't fix it.