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Jun 24, 2023
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I have some questions about fermentation.
I have read that hydrometer reading is the only way to be sure to the completion of the fermentation and bubbling activities in the air-lock is not the way to verify if fermentation has completed.

I have a couple of brew on going with slightly more than a week's time between each brew. My last brew is based on the recipe from brew's best RIS. This RIS with OG 1.066, its air-lock activities only lasted slightly over 3 days and then it seems to be not bubbling at all while the air-lock on the second last brew(OG1.047 with estimated 4.6% ABV upon completion) is still on going. I think this thread is on the same topic https://www.homebrewtalk.com/threads/fermentation-time.731681/ which means I have nothing to worry about and should just let it sit for at least 3 weeks. https://brewersbestkits.com/assets/1046_russianimperialstout_recipe.pdf from the instructions given is like fermentation should start within 1-2days time, once fermentation started take again 4-6days (likely to slow down which is the time to transfer to secondary and then let it ferment for another 2 weeks totaling to about 3 weeks time)

If one is brewing a stout, do they tend to be better if more time (more than 3 weeks) is given for their fermentation stage (https://www.homebrewtalk.com/threads/imperial-stout-fermentation-time-secondary-fermenter.729088/) and after bottling is also better to leave them for months?

I have a fermenter that shaped like a carboy where the cylindrical body sort of curved to form a slightly narrower opening. Thus curvature part is able to show any bubble that is still escaping from the yeast cake(those that are escaping from the yeast cake directly below the curvature area) at the bottom of the fermenter. I am brewing normal ale with DME and tomorrow is the 3 weeks mark yet I still sees bubble not though not enough to bubble through the air-lock. In such case should I wait till there is no more visible bubble escaping from the yeast cake at the bottom then bottle the beer or I can bottle them soon as it reaches 3 weeks in the fermenter?

One more question is that given same recipe with same everything from water, OG, FG, calculated final ABV, water, yeast etc except for the fermentable, will they have different air-lock activity time? (meaning only difference is in the fermentable will they have difference in term of the time length that the air-lock is actively bubbling?)
Let's see if I can hit all the major points here...

Yes. A gravity reading is the only way to tell if fermentation is complete. Once the same reading is taken three days in a row, it's safe to assume fermentation is complete.

The fermentation time is largely up to the yeast and temperature. The style and vessel's shape may have a negligible effect, but not measurable.

I will add that secondary fermentation is not longer required for the vast majority of brews as it could introduce oxygen or contaminants. Just leave it in primary for two weeks (assuming fermentation is completed by then) and transfer to your bottles. I find that it will take only two to three weeks to carb up in a bottle.
Even with the same ingredients, airlock activity might be different. Other reasons than ingredients affect that.

Beer isn't ready to remove from the fermenter just because it is finished fermenting. The commercial brewers move it out of their fermenters because they need the fermenter for the next batch. So they move it to something that is usually called a bright tank (I think).

It's less cost than a new fermenter would be. So that might be why they don't just buy another fermenter as a homebrewer might do to get that next batch on it's way.

If you've waited two to three weeks, fermentation is probably long since been over. Especially if the beer is clear and you can see across the top of the trub layer to the other side.
Im in qld.. and use kveik yeast in summer, so actual fermentation can be over in days not weeks. But then, as im using kegmenter, i condition beer over the cake, some say this is preferable to racking, some debate on this. I do this as i ferment and serve in same keg (kegmenter). Always allowing a week or so for suspension to settle on bottom so beer is nice n clear

So depending on yeast you use, and fermentation temperature, fermentation time can be quite different (in my limited experience!)
Hi all,

Thanks for the replies. Just done bottling yesterday.


@Rish are all stouts the same as in leaving them a bit (one week at least) longer than for beers or ale or it only applies to RIS?

Encountered one problem while bottling today(in the last bottling as well but forgotten to ask about it here), erm sometimes during bottling using the bottle filler with the spring stopper that trigger the open close there are time when some of the yeast cake thing slipped past straight into the bottle. Correct me if I am wrong but this solid (yeast cake or the dried up krausen on the wall of the fermenter) is not going to destroy the beer if some of it gets into the bottle, only thing is to be extra careful when pouring from the bottle when the beer is ready to drink. Tried to tied a mesh at the tip of the filler but the mesh screen size is too big that some of the solid in the filler just flushed through the mesh and went into the bottle. This is weird to me as the first bottle I fill was fine and this semi-solid(does'nt choke up the opening end of the filler) thing appears only during the second bottle. Since the mesh failed I removed it and then try to fill up the rest of the bottle and did not see any more of the semi solid thing. This is weird as I dunno where this solid stuffs comes from all of a sudden.

Anyone here completed 3 weeks fermentation with only first 3-4 days air-lock bubbling then the fermentation continue for the rest of the time until 3 weeks time is up without any bubbling in the air-lock(the floating piece of the air-lock rested completely on the little tube that let out the gas from inside of the fermenter?)

Also (not obsessed with air-lock but its the only thing that gives me the most sense as beginner), I noticed that there are difference in the center piece of the air-lock. If there is bubbling activity(even if its only once every 30mins or longer) the center piece will appear to be push towards the upper part and tilted at an angle. What confused me is when the center piece lies evenly flat just like when one has filled it with sanitizer and capped it before inserting it into the fermenter air-lock opening.

Thanks again for all the feedback.
all stouts the same
I was thinking about your RIS but I leave all my stouts in the fv for at least 4 weeks, usually 6.
yeast cake thing slipped past straight into the bottle
This is just stuff that hasn't settled or got stirred up as you were prepping to bottle. It won't hurt anything, just ends up as a little more trub in the bottom of your bottle. Glad to see you got everything into bottles! Give them 2-3 weeks at room temp and you should be ready to go!🍻
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