Stepping Fermentation temperatures in FV

Discussion in 'General Beer Brewing Discussion' started by Adamski, Dec 3, 2019.

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  1. Dec 3, 2019 #1

    Adamski

    Adamski

    Adamski

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    Hi All

    I have been homebrewing for a few years now, and understand that fermentation temp for yeast is critical to a good brew. I have been using a standard FV bucket, heat pad and inkbird controller to maintain temp according to kit instructions. So I generally control Fermentation at approximately 20-21 C. I have a GF Conical fermenter arrived today (early crimbo pressie to myself), and it has the facility to be able to step temperatures. Which for me begs the question is there an optimal temperature curve for yeasts. Perhaps something like 21c for a couple of days then dropping a degree every day or whatever best suits the curve. Household ambient temp is a pretty consistent 18-19C.

    I am using a dried yeast that comes with a kit, though to be fair I have sometimes hydrated it to form a starter.

    Part of the reason for getting the GF Conical FV was that, I am also interested in capturing used yeast for future use, and also reducing racking times to reduce sediment, this would allow me to select liquid yeasts and not be tied to the dried yeast provided in the kit.

    Opinions or a good steer in the right direction with regard to temp steps throughout fermentation will be greatly received.

    (I am on the fence with going all grain, I want to but I need to cost it out with regards to how logistically do-able it is. I live in Highlands of Scotland, and no decent homebrew shops within easy reach for supplies.)

    I've had a bit of a scan on the forum but couldn't see the answer. If this topic has been kicked around a lot and there's a link to the topic please point me that way, I don't want to waste peoples time on a well mused question.

    Thanks in advance.

    Adam
     
  2. Dec 4, 2019 #2

    steveinUS

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    My best results have typically come from holding a steady temperature, near the low-to-mid-point of a given yeast’s recommended temp range. If it’s a really big beer or a fussy yeast, and I’m trying to get it to finish, I’ll raise the temp a couple degrees every few days towards the end. Dropping the temperature during active fermentation could risk having the yeast stall. On the flip side, some Saison yeasts do amazing things by gradually ramping them up over a week into what would be unheard of for standard ales (up to 85F of higher).

    Also unless I’m misunderstanding, there’s no reason not to use liquid yeast strains with your kits if you like, regardless of the FV you use. You can also harvest yeast in your new conical (and congrats on that!) for future use, which started as a dry sachet in a kit. There aren’t as many strains available in dry form, but that has been changing.
     
    Last edited: Dec 4, 2019
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  3. Dec 4, 2019 #3

    johncrobinson

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    I used to use a very accurate temp controller made by Omron.It would hold temp to 0.1c of set point.
    I have found stability of temp the 100% great secret of avoiding problems with fermentation with wine over nearly 50yrs exp.

    My one and only stuck fermentation in all that time was due to me accidently swiching off the heater for a FEW hrs.

    Beers and lagers may be a bit different.Due to lower alcohol stress on the yeast.You will need other members who brew more beer than i do to advise

    Some wine makers also do vary temp during fermentation,But you need to be carefull..However variations are quite small in these cases.

    I too live in the highlands,And know of two hardware shops one in Inverness the other in Dingwall that have homebrew sections,Not an amazing range but much better than nothing.
     
  4. Dec 4, 2019 #4

    An Ankoù

    An Ankoù

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    I have no temperature control at all. I pitch at the higher end of the yeast's range- even for lagers and then try to bring the beer down to the lower end of the range once the surface is covered with the multiplying yeast. Bearing in mind that fermentation is exorthermic, the beer probably ferments a few degrees above the minimum anyway until the head drops. With lagers especially, it's important to raise the temperature a few degrees right at the end of active fermentation so the yeast can clear up any diacetyl, and then chill again for the lagering stage.
     
  5. Dec 4, 2019 #5

    Cwrw666

    Cwrw666

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    With regard to going all-grain.
    You can get everything you want delivered although I expect your delivery charge will be higher due to your location. The secret is to buy a full 25Kg bag of pale malt plus everything else you'll need for the brews you've planned to do with all that grain (hops, speciality grains, yeast) all on the one order so you only have one delivery charge.
    I live in Wales and get all my stuff from the Homebrew Company in the republic of Ireland.
    Doing this, all-grain is the cheapest form of brewing and also produces the best results.
    Only down side is that a brew takes up to 4 or 5 hours!
    If you're already brewing kits the only extra equipment you need is a boiler of some sort plus a grain bag if you're doing BIAB which is the cheapest way of getting into all-grain.
     
  6. Dec 4, 2019 #6

    PhilBrew

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    Hi Adam

    ... I'm afraid there are not likely to be any simple answers to that question ... ultimately, you are the head-brewer in your home-brewery and the "best" temperature curve for you to adopt will depend on what you are hoping to achieve by managing the temp and any changes in it :?:

    Having said that, there are some general "rules of thumb" that I'd say you should consider when deciding what you'll do ...
    • yeast finding themselves in environments where conditions are improving (including rising temperatures) will tend to ...
      • multiply and ferment more rapidly, where the environment also has sufficient nutrients (oxygen and sugars being the main ones that we beer fermentationists would worry about) to support population growth, which will tend to create more yeast derived flavours; and/or
      • be less inclined to flocculate, where the environment has diminished nutrients (like near the end of fermentation (as per the "diacetyl rest")), and more inclined to ferment any remaining sugars (tending to lower FGs, drying the product out) and more likely to "clean up" partial bye-products of fermentation (such as acetaldehyde and diacetyl);
    • yeast finding themselves in environments where conditions are becoming less favourable (including lowering temperatures) will tend to ...
      • multiply more slowly (possibly to a lower overall population) and ferment less rapidly, where the environment has sufficient nutrients to support population growth, which will tend to encourage a "cleaner" ferment (throwing fewer yeast derived flavours);
      • be more inclined to flocculate, and less inclined to consume any remaining sugars (if there are any) or "clean up" partial bye-products of fermentation (if there are any).
    With that info you'll learn to read what other brewers may be trying to achieve when they describe the temperature profiles they apply to their ferments ... e.g. if a profile is described as, say ...
    1. pitch at 18C (low-mid in the yeast's range)
    2. allow to free-rise to 20C (encouraging the yeast to grow rapidly and leave their flavour impression on the product)
    3. maintain until 70% apparent attenuation (let the yeast get on with fermenting, at a constant temp, in the middle of its range, for the majority of the ferment)
    4. increase to 24C (to get the yeast to "clean up" (you could call this a "diacetyl rest" if you wanted)) until gravity stabilised (FG reached)
    5. cold-crash down to 5C (get the yeast to flocculate out)
    ... you'd understand why each step is being added, and may conclude that that would be a good temperature profile for a beer that you wanted a decent amount of yeast impression in, without dominating .. for an English Pale Ale, say (which it would) ... but then you'll also understand why an American Pale Ale, or Lager, or Saison, or German Wheat Beer, brewer might choose a completely different profile :?:

    Hope that helps,
    Cheers, PhilB
     
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  7. Dec 5, 2019 #7

    Litmus

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    I think the variety of answer and approach to this show that it's really a matter of preference. If you want the impact of the yeast to be minimal ferment at the bottom end, mid to high if you want more impact. @PhilBrew list is a great starting point. Do experiment though, I will give you an example I make a Wheat beer if I allow a free fermentation it comes up with much more banana, if I control at the bottom end it produces much more of a peppery clove spice and only just detectable banana. Hope that helps a little.
     
  8. Dec 6, 2019 #8

    Adamski

    Adamski

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    Thanks everyone for the terrific responses to this question.

    Reading between the lines, it would seem that stability is the key element throughout the process.

    Starting at a higher temperature will tend to cause a more yeast influence on taste. Whilst running at a lower temp will be less yeasty.

    I have in the past cranked up the temp a couple of degrees to finish the brew.

    I definitely appreciate the exothermic reaction heat increase, which well lends itself to initially a slightly lower mid temp.

    I am curious about yeast attenuation @ 70%, in so far that you completely lost me Phil, apologies.

    In essence it would seem that experimentation and personal taste is the answer to the question.

    I have been doing Russian imperial stout kits (from love brewing) which have come out well, and love Guinness Foreign Extra. The next time I do this kit I will have a bit of an experiment with a different temp set up.

    With regard to all grain, albeit a sideline thread, my concern would be with the amount of bulk storage I would require and shelf life of product.

    Thanks so much for the detailed and time consuming comments, probably over 100 years of experience and knowledge above this post! so much appreciated and I will strive on towards perfection!
     
  9. Dec 6, 2019 #9

    PhilBrew

    PhilBrew

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    Hi Adam

    ... sorry, too much terminology will always confuse :confused.:

    If you express specific gravity as "points" (so 1.040 becomes 40 gravity points), then you can calculate the drop in gravity at any time during a fermentation (SG), and express it as a percentage of the gravity points before fermentation (original gravity or OG) ... to give you the apparent attenuation of the fermentation ...
    ((OG -SG)/OG)*100 = AA%​
    ... and the specific gravity when fermentation has finished is final gravity (FG) and the apparent attenuation then is the overall (apparent) attenuation of your yeast ... most yeast strains will tend to ferment (beer) to around 70-80% attenuation, but if you mash warm or cool you can affect that, and the occasional yeast strain (like a saison or a brettanomyces strain, say, might go much higher).

    Basically, AA% is a measure of "how far gone" your ferment is ... and if you have a "ballpark" notion of what FG you're likely to get, it can indicate how much more fermenting there is still to do :?:... which some may feel can be a little more accurate than relying on ferments taking a certain number of days, say :?:

    Cheers, PhilB
     
  10. Dec 6, 2019 #10

    Adamski

    Adamski

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    Thanks Phil that makes a lot of sense, apologies for the confusion. As you correctly ascertain and allude to, I would set the temp leave for about 12 days, check SG and if close to finish FG, up the temp a degree, and generally rack 2 days later. With the new fermenter (which the wife has set up / I'm working in Italy (we're both engineers)) it will be easy to take a sample of beer for taking gravity readings.
     

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