In the future I would like to get a tilt hydrometer or something of the likes, but in the mean time I love how the data logged by BrewPi gives valuable insight into whats going on inside the beer. I can judge how active a fermentation is by the delta between beer set point and fridge temp. For those who like to drive primary fermentation by raising the temperature set point, at what point do you like to start this ramp? I know many like to judge fermentation by their airlock activity. I myself don’t take the time to look inside the chamber often, maybe i’m lazy… In the past i’ve waited until the temperature delta zeros out. Lately, i’ve been starting to ramp before this delta curbs off completely, thinking it might be more productive to minimize the slow down of yeast activity.
Does anyone have any beliefs on the proper time for a temp ramp? Do you notice a difference starting a bit earlier or tad late?
Most of my experience is in simpler ales. Does style affect your strategy?
Maybe I should finish read yeast which has been sitting on the shelf for a while now… I can’t say I been very active on the forum myself, but I would love to see some more discussion of temperature profiles. After all, that’s whats BrewPi is all about!
I’ve just finished the Yeast book myself and it’s very good.
What do you mean by driving fermentation? I ramp to encourage certain flavours, to avoid stalls, and occasionally when I crash. In any case, I tend to ramp over the course of ~24h to avoid thermally shocking the yeast.
Ramps for flavours depend on the yeast and which flavours you are trying to encourage. I would read the flavour sections of Yeast and search online for what other people are doing with that yeast. It’s often said that flavour is mainly generated in the first 3 days and it’s safe to ramp up after that to discourage stalls. While I’ve found thats sort of true, remember that not all strains behave the same and that some flavours are dependant on activity late in fermentation (e.g. diacetyl). It’s also worth noting that many strains are relatively clean fermenting and relatively reliable across a range of temps as long as you keep them stable. I generally won’t use complex profiles for British and American strains for this reason. I mainly use ramps for Belgians and the one lager I’ve done. Many of the recipes on Candi Syrup Inc’s website have ramps so they’re a good place to start http://www.candisyrup.com/recipes.html . While I often ramp at fixed times or “towards the end of fermentation”, with saisons I have taken to keeping an eye on my Tilt. If I see activity subsiding early, I’ll ramp up a few degrees over 12-24h. If I’m cold crashing but want the yeast to continue cleaning up the beer after the crash, I’ll make sure I ramp that rather than going as quickly as possible.
With regards to judging when to ramp based on the air lock. While you can, remember that this will be inaccurate/inconsistent. Airlock activity depends on many variables. Cell count, viability, vitality, strain, mutations, air pressure, etc. It will also continue after fermentation finishes as some of the dissolved CO2 comes out of solution.
I would also say that if you’re ramping, try to understand why. I don’t think there’s much benefit in ramping for the sake of it. And you’ll be able to make the most in the long run if you understand what you are doing and why. I consider myself quite early on this path. But I think I’m one of maybe 2 in my local homebrew group who regularly ramps. And I think the other person mainly does it to prevent picky yeasts stalling, not for flavour.
I admit I have much to learn about yeast and fermentation. I suppose by “drive fermentation” I mean accelerate. I tend to ferment on the lower side of the suggested temperature range. Around day 3, when things start to slow down I slowly ramp the temperature up closer to the higher end of suggested temperature range. I usually ramp over 3 days time. This may only prevent stalls, but I assumed it would help me achieve a full and proper fermentation in less overall time.
I don’t brew as often as i’d like, and I almost always want my last batch tapped as soon as possible. I brew session IPAs most often, with dry hop additions. I’ve had no issues drinking these as soon as they’re carbonated. Other ales I let sit in the Keg a while to condition. As memory serves me, a healthy controlled fermentation of a simple beer doesn’t need 2+ weeks in the fermentor to be done right, and can actually be finished up far less time in some circumstances. I suppose my intent is to ferment these IPAs as quickly as possible without sacrificing quality. Although, I can’t say i’d be able to distinguish a small change for better or worse. My experience and palate isn’t up to snuff.
If you’re brewing IPAs with something clean like US-04 or WLP001, I wouldn’t bother with the ramp up. They’re so quick and reliable anyway that any benefits seen would probably be outweighed by the amount of time it’d take you to spot it’s ready to drop. The ramp won’t do any harm, but I think the effects will be negligible in both time and flavour. Just pitch an appropriate amount of healthy yeast and keep it steady at the upper end of the recommended range and it’ll go as fast as its going to. If you’re keeping the temp stable, you’ll only really have to worry about stalls with those if you’re doing very high gravity beers without an appropriate starter.