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Consistently missing FG target

Discussion in 'All Grain Brewing' started by Ckilner, 22/9/19.

 

  1. Ckilner

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    Posted 22/9/19
    I have a Braumeister 50L and a temperature controlled SS Brewtech Unitank. I use Beersmith (and have been doing for a number of years) to design my recipes.
    I have recently adjusted my mash schedule to reduce the mash time as I have read that a multi stage mash is not really essential these days with the modified malts that are available.
    I mainly use Maris Otter and Torrified Wheat in my brews and I have set the mash efficiency to be around 80%.
    I consistently hit target OG but I now consistently miss FG - it always seems to be about 1.020 (rather than the 1.012 or thereabouts that I'm aiming for).
    My mash schedule is: (medium body)
    Mash in: 65 deg C
    Maltose: 67 deg for 45 mins
    Mash Out: 78 deg for 5 mins

    It seems I'm getting the sugars but they're not all fermentable?
    What should I adjust in the mash schedule (assuming that's the problem) ?
     
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  2. Drewgong

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    Posted 22/9/19
    Maybe you can include your fermentation details as well ...temp yeast starter ect ect just incase it is a fermentation problem . Some people can taste the sugars in a beer that hasnt dropped right down .....im not one of those people lol
     
  3. YAPN

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    Posted 22/9/19
    I had a FG problem for two years. Eventually fixed it by pitching double the amount of yeast.
     
  4. MHB

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    Posted 22/9/19
    Mash in cooler (under 60oC), Beta Amylase is quite fragile and if you want dryer beer it can take a bit of a hammering if it going in too hot.
    Try mashing around 63-64oC, hold for about 1 hour and ramp to 78oC for your mashout.
    Mark
     
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  5. Ckilner

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    Posted 22/9/19
    I use Fermentis S-04
    * Ferment 20 Deg C for approx 5 days.
    * Dry hop at 14 deg C for 5 days
    * Cold crash 6 deg C for 2 days

    After 5 days at 20 deg the activity has stopped and it's hit 1.020
     
  6. Ckilner

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    Posted 22/9/19
    I use a 2L yeast starter in a 40L batch. The first time I had this issue I chucked in another 2L starter but that made no difference
     
  7. Ckilner

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    Posted 22/9/19
    I used to mash in at 40 deg for 20 mins, then raise to 52 deg for 20 mins and then maltose.
     
  8. Ckilner

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    Posted 22/9/19
    Perhaps I'll try:
    50 deg for 20 mins
    67 for 45 mins
    78 for 5 mins
     
  9. MHB

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    Posted 22/9/19
    I don't think you need quite that intensive Glucan and Protein rests, particularly with a malt like Maris that is a very good choice for isothermal mashes.
    When brewing on a BM I mostly mashed in at ambient (~20oC) and let it ramp to first rest usually around 63-64oC. As the temperature goes through the ranges for the enzymes they have plenty of time to do what needs doing.

    You say this problem has started since you started doing shorter mashes, might be a bit of a hint there!
    Mark
     
  10. Ckilner

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    Posted 22/9/19
    I agree, a bit of a hint but not sure which step in the mash schedule messed it up - the price of changing more than one thing at a time. Schoolboy error.
     
  11. keine_ahnung

    joeblogsbier.com

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    Posted 22/9/19
    Mark is on the money here. Although going under 60°C is not necessarily beneficial. I'd mash-in at 60°C, rest at 62°C, then a more intensive rest at 67°C. Quick rest at 72°C, then mash-out at 78°C.
     
  12. Ckilner

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    Posted 22/9/19
    Cheers all.
    I'll try the new mash schedule next brewday in a few weeks.
     
  13. BrewsWayne

    Pro Pro

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    Posted 22/9/19
    Are you measuring FG with a refractometer or hydrometer?
     
  14. Ckilner

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    Posted 22/9/19
    Hydrometer at 20 deg C
     
  15. sponge

    Dungeon O' Sponge Brewery

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    Posted 22/9/19
    Does your hydrometer read 1.000 with water at 20'C?

    Have you calibrated your thermometer(s)?

    As previous, ramp up mash from ambient then a long, low rest at 63/64 for an hour with a big, healthy yeast starter will get you dropping points in no time.
     
  16. Dan Pratt

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    Posted 22/9/19
    Fom what I read two things are the stand outs:
    1. Mash temp at 67c - quite high and leading to a higher FG
    2. Yeat Strain - S04 - a low attenuating yeast
    These 2 things combined are seeing a higher FG, interested to know if they taste sweet, to me 1020 would be on the sweeter side.

    I would suggest as Mark described running a lower rest phase @ 63-65c, this will dry out the beer and with the 20% T Wheat the body should be ok, if not add some carapils next time. Also, using a Chico strain yeast US05, 001, BRY97 etc etc, this strain attenuates better and will work well with the lower mash profile.

    Offcourse, change 1 thing at a time and find your flavour.
     
  17. JDW81

    I make wort, the yeast make it beer.

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    Posted 23/9/19
    Couple of other things to consider are yeast and dry hopping time (although may only be playing a very small part compared to your mash).

    If you're under pitching then you may be stressing the yeast and have trouble reaching your desired FG (particularly if you're making wort with gravity on the higher side). Do you use a yeast calculator and adjust the pitch rate accordingly?

    Other thing is hops. They will inhibit the yeast to a certain extent (depending on how much you put in). Hops have anti-bacterial properties and if you already have stressed yeast, chucking in a big load of dry hops may well reduce it's activity further. As a general rule the recommendation is to dry hop when you're around 2-4 points away from your expected FG (this is in one of my HB books, but can't find it at the moment so no reference unfortunately). I think I've heard JZ/JP talking about this as well, but haven't listened to brewstrong for a while so could be making things up.

    Hope you solve the problem!

    JD
     
  18. Ckilner

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    Posted 23/9/19
    A good point re. hydrometer. I'll check that today.
     
  19. Ckilner

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    Posted 23/9/19
    I usually make a 2L starter from 200g of DME in 2L water. Boil, allow to cool and then add a pack of yeast (S-04 in this case) and then leave for a couple of days (max) on a heat controlled stir plate at 20 deg C. I use a 2L starter in a 40L or 60L batch. The recent cases of low FG have been with 40L batches and 2L starters.
     
  20. MHB

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    Posted 23/9/19
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