does anyone ferment with the hydrometer in the carboy?

oliver

Well-Known Member
Premium Member
Joined
Sep 21, 2015
Messages
1,039
Reaction score
482
Points
83
I brew small batches and have no idea when my beer is ~50% attenuated.

I was thinking about just putting the hydrometer in the glass carboy and watching it drop over time? But then how do I safely get it out without breaking the fragile little thing?

Anyone have experience with this?
 
I know that some do it. I never have, for two reasons. One, of course is breakage. The other is once krausen sticks on the hydrometer, it wouldn't be very accurate and it would be very hard to read through the glass with the krausen stuck on it even if it would be accurate.
 
the best thing to do is just wait 2 weeks, almost all ales will be done in 10 to 12 days, at day 7 give it a swirl then wait and your ready
 
the best thing to do is just wait 2 weeks, almost all ales will be done in 10 to 12 days, at day 7 give it a swirl then wait and your ready
Trying to lagers, and ramp temperature when I get to 50%
 
doing lagers at 2.5 gallon batch size hasn't been easy yet, I've ran into acetaldehyde a lot, really prevalent green apple in my light colored lagers. It gas something to do with my fermentation and aging, but I've also noticed the same green apple flavors on Belgian ale yeast in the past.
 
I've done lots of 3-gallon lagers with no acetaldehyde. It's another problem and if you're getting it on unrelated beers, start checking everything for scratches or crannies where bacteria can hide. And it's easy to mistake acetic acid for acetaldehyde. Disinfect everything and try again! Another possible problem is interrupting your fermentation - acetaldehyde is a precursor to alcohol.
 
And to OP's question, no. Too hard to read in there and I can steal a couple drops and read gravity using the refractometer.
 
This is a VERY general rule, and you won't find it anywhere else, but if you have a fermentation lock, check the number of bubbles per minute regularly. Once the number of bubbles per minute reaches a peak (usually about the time the krausen starts to drop), make a SG measurement 2 days later. If you are 2-5 SG points away from FG, you are ready for a diacetyl rest. If it still higher than that, measure again the next day. For me, with lagers, this has been almost a foolproof way, regardless of the intensity of the bubble rate. It's almost always ready for a diacetyl rest 2-3 days after peak bubbling.
 
  • Like
Reactions: J A
I saw something for sale once that was different weighted balls that you could drop in the carboy and based on where they were floating you could read the gravity. Never used it though. Also seen computer gizmos for tracking gravity.
I have never found the need to check the gravity during fermentation. If I'm doing a lager I do the d rest when the krausen falls.
 
Trust your yeast and you won't necessarily need a reading. Most lager yeasts will attenuate within 5 days at the top of their preferred temperature range. It could take twice as long near the bottom of their range. If I'm doing a typical lager, I'll pitch at below 60 and keep the temp at 59 for 3 days and then ramp up fairly quickly. If I decided to keep it lower, say 52-54, I'd give it 5 days and ramp.
Mostly you can tell by the krausen. At the higher end of the range, it'll krausen almost like an ale and then start to settle a couple of days later...that's the ramp up point. If it's lower in the range, the krausen will be thinner and less agressive, but there'll still be a lot of movement within the wort. When that slows and whatever krausen you have starts to diminish, you're safe to start raising. Sometimes the airlock will give you enough to work with... A day or so after it peaks in activity it'll start to drop pretty steadily and that's a good time to raise.
I don't bother taking a reading until I'm a few days in and I've never seen anything less than about 70% attenuation.
 
Last edited:
good responses .

I brewed a doppelbock last night, pitched at around 5:30PM at ~60ºF, chamber quickly dropped it to 55 when the probe went in.

This morning, good amount of kraussen for a lager at 8:00AM. But this has got to be just the beginning.

I think I have to guess, probably tomorrow night if it's slowing down I'll let it free rise.
 
What yeast?.
A dopplebock may take a little while to attenuate fully and you don't want a stuck fermentation so you should control temps carefully. Your pitch temp sounds good and 55F is a sweet spot for most lager yeast fermentation. Strong kausen in 12+ hours indicates great yeast health and a good starter. Be aware that air temp will be a few degrees lower than an actively fermenting wort so hold your 55 and you'll be fermenting at maybe 58 which should be fine.
I'd let it go a full 48 hours from full krausen and let it come up a few degrees a day so that by the end of 6 days from brewing, you'd be at 68 degrees. For a dopplebock, I'd hold there for a week before dropping temp no matter what the gravity says. With any luck, you're at 50-60 percent on day 3 and still have a few points to go by the time you get to D-rest temp. What you'd like to avoid is a fully attenuated fermentation at a really low temp. Fortunately, given that you're staying in the high 50s for the early fermentation, diacetyl production should be pretty low and you don't have to worry much anyway.
 
pitched a 1 liter starter of 34/70 into 9 quarts of wort at 18.5ºP, but the 1 liter starter made the brew day complete at 10 quarts of 17.6ºP wort.

I'm using a thermowell, so no need to worry about ambient temps and such.

I like your idea, I'll give it 7 days of primary fermentation while ramping the temp to ~70ºF on day 7. I'll do the math on that tonight and ramp it gradually regardless of attenuation progress I think.
 
  • Like
Reactions: J A
Your 34/70 will go pretty quickly. It likes warmer temps and stays clean even over 60 degrees. I wouldn't be surprised if you saw 50% attenuation in the first 36 hours, depending on OG.
Sounds like you got it! :)
 
I brew small batches and have no idea when my beer is ~50% attenuated.

I was thinking about just putting the hydrometer in the glass carboy and watching it drop over time? But then how do I safely get it out without breaking the fragile little thing?

Anyone have experience with this?
I use a Tilt Hydrometer and am very happy with it. Just takes a click on the Tilt App on your phone to get a gravity reading any time you like.
 
I use a Tilt Hydrometer and am very happy with it. Just takes a click on the Tilt App on your phone to get a gravity reading any time you like.
That really looks interesting. Reviews have mostly been positive. It would help a lot with lagers, I usually just raise the temp for a D-rest when the krausen falls (not always the best indication of fermentation, but it works), but live monitoring of the temp is really cool. No pun intended.
 
  • Like
Reactions: J A
That really looks interesting. Reviews have mostly been positive. It would help a lot with lagers, I usually just raise the temp for a D-rest when the krausen falls (not always the best indication of fermentation, but it works), but live monitoring of the temp is really cool. No pun intended.
I do like the fact that I always know what the gravity is particularly as I use stainless steel fermenters and can't see what's going on in there.
I suppose it makes it a lot easier to gauge the progress if using a glass carboy though.
 
I've found that with experience, I can depend less on measurement and monitoring. After you've had a few batches with a particular recipe or yeast behave a certain way at a few different temps, it's pretty easy to extrapolate and get very close. I still like to steal a sample, especially with a lager, to see how things are going, but I could run most batches from start to finish without any readings at this point.
Take notes and refer to them often. ;)
 

Back
Top