hydrometer

[jthoward013]

i know how to take a reading on the hydrometer but dont have a clue what it means. i know you are spost to start high and end low. but does the lower number mean you have a lower alcohol content or not. for example my batch started at 1.080 and i checked today and its at 1.035 after 4 days. the reason i checked it is there are almost no bubbles from the airlock. my local brewshop owner says it should slow and to let it work for another week and a half but to keep a look at the hydrometer every few days till it stops moving.

 

[TyTanium]

Other things equal, lower final gravity means more alcohol. What you're measuring is how much of the sugars the yeast converted to alcohol. You start with 1.080 and as the yeast eat the high-density sugars and convert it to lower-density alcohol, the gravity drops. The more it drops, the more alcohol. Again, that's only if everything else is held constant. For a 1.080 beer you'd most likely want to finish around the 1.020 range, depending on style. Age is your friend with big beers, so I'd take your brewshop owner's advice here and just leave it. No need to check gravity every few days though - just leave it and check again in 2 weeks or so.

 

[NordeastBrewer77]

i suggest some basic reading on the subject of home brewing. try this book out, it's a free internet copy. it's one of the two books folk refer to as the best 'how to' books on the subject.

 

[jthoward013]

i suggest some basic reading on the subject of home brewing. try this book out, it's a free internet copy. it's one of the two books folk refer to as the best 'how to' books on the subject.

thanks for the link. skimmed through it some and now have a better idea about hydrometers now and ill save it to my bookmarks so i can reference it later.

 

[NordeastBrewer77]

thanks for the link. skimmed through it some and now have a better idea about hydrometers now and ill save it to my bookmarks so i can reference it later.

i always have that site bookmarked. i regularly reference that book or Papazian's "complete joy......". some of the material is dated, but there's some much needed info in those books.

 

[yimmyyames]

I just wanted to piggyback on this thread rather than start a new one since the subject matter is similar. I was looking for some further clarification on the hydrometer since all things regarding the tool seem to confuse me. Specifically, I currently have my second batch in the primary fermentor which has been there about 10 days and all bubbling has stopped. After reading this board frequently it has become obvious how important the need to understand and take hydrometer readings (I didn’t use it on my first batch since I made the beginner mistake of breaking it while washing it). I want to transfer my beer into a secondary fermentor (I don’t want to turn this into a discussion of why it isn’t necessary to use a secondary fermentor) but I’d like to confirm it is in fact ready for the move and it sounds like the only way to truly know that is to use a hydrometer.

So, is it just a matter of opening the primary and dropping in a sanitized hydrometer and taking a reading for 3 straight days (I don’t have a thief at the moment)? If so I guess I am thinking it is more complicated than it is but confirmation from someone much more knowledgeable than I would be more than welcomed.

Thanks in advance.

 

[unionrdr]

If you have a baster,clean it in PBW,then soak it in starsan for a couple minutes. Then take a sample & fill the tube the hydrometer came in to test it. I don't take a hydrometer sample till the 2 week mark. That gives me an idea of about how long it'll take to get to a stable FG. Then take FG samples 2 days apart to confirm that it's done.

 

[Hang Glider]

most hydrometers come in a clear plastic tube. Northern Brewer and others sell test jars for very cheap - next time you place an order, get a test jar.

With a wine thief or turkey baster, (sanitized!) remove enough sample to float the hydrometer in the tube or test jar. Do NOT return the sample to the fermenter.
Turkey basters are available at your grocery store.

Read the number at the low point of where the line touches the hydro - look up meniscus on wikipedia - you read the bottom because the glass "draws liquid up it's sides" and is not accurate.

 

[yimmyyames]

Thanks for the information. I do have another dumb follow up question. In order to put enough beer in the clear plastic tube I needed to add about 4 oz of beer. So if I take a reading three times, aren't I essentially losing 1 beer? I hate to waste any beer but I guess it is necessary?

 

[ArtimusBeerimus]

Necessary evil... Although you can limit the need for excessively multiple readings by simply giving the beer enough time.

 

[WhiteEagle1]

I usually just take one reading post boil, then a second reading at the 3 week mark and record right before I bottle. My air lock activity is usually very very slow to non existent after about a week and a half to two weeks. Odds are pretty good its done fermenting at the 3 week mark.

 

[Hang Glider]

yes, technically readings three days apart...but if you've let it condition for 4 weeks, and you test it - you're probably good. However, if you're NOT good, then you add some more yeast (that spare pack of Notty, or some Champagne yeast) and wait again. Test before moving!

and, it's not really wasted - you ARE tasting, aren't you?

 

[Trokair]

Whole point of a theif to me. I can drain the sample against the neck of the carboy, no beer lost.

 

[Hang Glider]

Whole point of a theif to me. I can drain the sample against the neck of the carboy, no beer lost.

that's all good as long as you're extremely sanitary the whole way.
Personally I don't think the sample is worth the risk.

 

[petey_c]

Thanks for the information. I do have another dumb follow up question. In order to put enough beer in the clear plastic tube I needed to add about 4 oz of beer. So if I take a reading three times, aren't I essentially losing 1 beer? I hate to waste any beer but I guess it is necessary?

It's not a waste if you drink it...