Mash Rest Types, Temps, and Reasons

Discussion in 'General Brewing Discussions' started by jmcnamara, Jun 17, 2016.

  1. jmcnamara

    jmcnamara Well-Known Member

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    i'm slowly piecing together a little handwritten journal of brewing basics (think sean connery's holy grail notebook in the last Indy movie) (I also consider that franchise a trilogy).

    i just do a single infusion mash, which as I understand it is essentially another name for a saccharification rest.

    So,

    Sacch rest - 148-156ish - gelatinize starches, extract sugars, etc.

    I know i've heard of an acid and protein rests, but are there any others?

    are there specific instances when these rests are useful or are they largely throwbacks to historical brewing and undermodified malts?
     
  2. Nosybear

    Nosybear Well-Known Member

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    Short answer: With modern malts, anything other than a single-infusion, batch-sparge process is likely not necessary. I checked my conversion efficiency over many mashes between single-infusion and step mashes and the difference is not statistically significant. I haven't done enough decoctions to compare.
    Longer answer: If you're using a lot of Continental, lightly kilned malts such as pilsner, a protein rest at 122 degrees can help clarity. Likewise, if you have a lot of adjuncts and don't want a hazy beer, do the protein/beta glucan rest to soften up the gums and get rid of haze. The acid rest is a German answer to getting proper pH while still conforming to the Reinheitsgebot, in effect, giving the malt time to develop lactic acid. It's not necessary if you don't mind using acid to adjust mash pH or use acidulated malt. If you're doing a Hefeweizen and want clove flavors, hold off acidifying your mash and rest it at about 110 degrees for about ten minutes to develop ferulic acid.
    Decoctions are generally not necessary for conversion, the jury's out on flavor. Use them if you want but they're not necessary to convert starches. There's even a shortcut for decoction flavors: Melanoidin malt.
    So many of the rests are throwbacks, some are still useful but for most beers, single infusion is the way to go.
     
  3. artbreu

    artbreu Member

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    I use no-sparge (whole volume over the flame) with two rests: 148 and 162. I experiment with the timing on them. Sometimes 30/30min and 40/20, etc. using the highest flame I can muster during the rise. Then I burn again to 172 for mashout (assists the no-sparge lautering).

    I don't even remember where I picked this up but these are, to my understanding, the optimal temperatures (148 and 162) for maltose production.

    As far as reasons are concerned, I can almost guarantee this is not the "best" method... whatever that would mean, but I do know I get consistently high attenuation at the extreme cool side of optimal fermentation temps for my yeast. Since I like dry and clean, low ester beer, this works for me. It's also very easy to achieve on the stovetop.
     
  4. Nosybear

    Nosybear Well-Known Member

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    Those temps are the based loosely on optima for alpha and beta amylase, the two main saccarification enzymes. Beta Amylase is the lower of the two and the main contributor to "fermentability", that is, simple sugar production, with peak efficiency at about 142 degrees. Alpha Amylase is the higher of the two and leaves a lot of dextrines behind, producing more viscosity and "mouthfeel," peaking at 158 degrees.

    162 degrees will produce a very thick wort. The "window" for enzyme activity is 147 degrees to 158 degrees. The optimum single temperature is 153 degrees F (67 degrees C). Shifting a couple of degrees plus or minus from that point can have a substantial effect on your wort. For my single infusions, I generally aim for the desired temperature and let it drop a bit through the mash.
     
  5. jmcnamara

    jmcnamara Well-Known Member

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    slightly off topic, but i'd love to have my temp control solid enough to do comparisons on what a degree or two in mash temp would do for the finished beer
     
  6. artbreu

    artbreu Member

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    Maybe I get away with it because most of the conversion is completed in the first rest at 148. There's also some time that it takes for me to rise to 162 with a full volume. I wouldn't say my brew contains a lot of dextrines but I definitely don't get a light mouthfeel either.
     
  7. Nosybear

    Nosybear Well-Known Member

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    Likely so. Key is, to the original question, unless you know it's necessary, why do it? If you don't know why, you're extending your brew day for no reason. First, at 162 degrees, you're denaturing your beta amylase and operating above the optimum of the alpha amylase range. 158 should do just fine for your second rest. Second, with well-modified malts, most of the malts produced today, you don't need the step mash. A single rest of an hour at 152 degrees +/- 3 degrees works fine for me and I can find no difference in conversion between the single infusion and stepped mashes - I've collected the data and compared them. I add a rest, usually ferulic acid or protein, depending on what I'm making, only when I need to. I, too, like dry, clean beers and have no problem getting them using the single infusion.
     
  8. jmcnamara

    jmcnamara Well-Known Member

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    i usually go by the axiom "less is more"

    the less hassle I have on brew day, the more time there is for beer
     
  9. artbreu

    artbreu Member

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    If I'm honest at this point I would say I do it this way because it's become routine.. not a great answer. As I said the justification for it was the wort sugar profile, as in which sugars are produced. Conversion and attenuation data won't give you that.

    That being said, I don't have an analysis of my wort handy :)

    As always though, maybe it's time for me to try my process differently and see how I like the change.
     
  10. jeffpn

    jeffpn Well-Known Member

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    Or, if it ain't broke, don't fix it. Obviously if you're wanting to shorten up your brew day, that's one thing. If eliminating a step saves you time, and there's no significant change in your beer, then great! But if there is a change you don't like, then you have to figure out what to do to fix that, if not return to your original routine. It's all in what it's worth to you. You could compare your issue to the fact that I secondary everything. Everyone says not to do it. I just like to do it, so I do it.
     
  11. jmcnamara

    jmcnamara Well-Known Member

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    I'll second the secondary comment
     
  12. artbreu

    artbreu Member

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    There's more than one way to skin a cat, comes to mind.

    I don't secondary. Not because I don't think it's necessary—it's a common practice and part of your process done for a reason—but because I primary for a long time, use gelatin for fining if I care about clarity, and I keg condition (which is a secondary/serving vessel in my mind anyway). I can get the beer crystal clear with zero haze warm or cold, just the same. Totally depends on you.

    That being said, when I started brewing the community was a lot smaller. A lot less knowledge was available online, so we figured things out and developed our own processes. Still good to share what you do, see what other think about it, and rethink yourself if something makes sense.
     
  13. Nosybear

    Nosybear Well-Known Member

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    I, too, generally put everything into secondary although there is nothing to support doing so. So there's something to be said for habit. I'm trying to think of other "beer lore" I'm using in my processes. It took me a while to get over step mashes, for example. Or to realize that decoctions were more for the brewers' conversations than for the actual beer. Someone will always come up with, yeah, I tasted that, after you've told them it was an extract beer (I've never personally experienced "extract twang") or that you did a single-infusion mash instead of a dreimaischverfahren (three-step decoction with comment, yeah, I missed a bit of malt/complexity/je n'e sais quoi). As Jeffpn says, if it's working for you, it's working. Period. I don't have time in the brew day for unnecessary steps so I don't do them but that's my brewing. But, and I emphasize this frequently and often, it's important to know why you are doing the step you're doing, what outcome you are expecting from the step, are you getting the outcome and can you get close enough by omitting or reducing the step. Otherwise, it's beer lore.
     
  14. jeffpn

    jeffpn Well-Known Member

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    Here's a related question. My setup: BIAB and propane turkey fryer with 44 qt pot, 7 gallon (or so) mash. On a single temperature mash schedule, how do you maintain your temperature? This assumes you're your own thermostat, so to speak. I've settled into starting my mash 1-2°F warmer than my intended temperature. I check it every 15 minutes, and when the temperature falls to 1° below my mash temperature, I turn the heat on low for a minute or two.
     
  15. Ozarks Mountain Brew

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    the best way to maintain a constant temperature is to use a pump with a probe and honestly the temperature varies greatly from top to bottom if using an analog probe so a digital pt-100 probe hooked to a t coming out of the ball valve is the best way to read the temperature then recirculate over the top slowly and you can maintain within 1 degree up or down even with a propane burner, you just leave the burner on and manage the throttle and your set, you don't have to buy an expensive pump either a 12 volt high temp pump will work about $25, plus hoses and fittings ... I stated out that way when I started with BIB

    this looks fancy but its just an 10 gallon aluminum turkey fryer converted to electric, you get the idea
     

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  16. jeffpn

    jeffpn Well-Known Member

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    Interesting set up. But going back to the simplicity part of this thread, I don't see myself adding an electric pump to my process. I've never even used one for any brew I've ever made. That poor cat has been skinned so many ways!
     
  17. Ozarks Mountain Brew

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  18. jeffpn

    jeffpn Well-Known Member

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    23 minutes? I'll skip it and assume that the guy used propane for a while, and then decided that there's no other way to brew beer except to go electric. I ran the gamut on my smokers. Started with charcoal, moved to propane, and now I have an electric smoker. With the extended cook times of a smoker, electric is the way to go, for me. I can't see converting my brewing to electric. I just don't have to make that many adjustments for an extended period of time. One hour mash with the burner mostly off, and a one hour boil with no adjustments once the boil commences.
     
  19. Ozarks Mountain Brew

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    the actual point is a perfect mash temp can be easily done with electric
     
  20. jeffpn

    jeffpn Well-Known Member

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    Soooo... I'm right! :lol: Easy or not, I just don't see myself buying (or even using if it were given to me for free) electric equipment. I like the minimal amount of space my equipment takes up now when I'm not brewing. And if I bought an electric set up and a pump, that's just more to clean. Gotta keep that brew day as short and as easy as you want to!!
     

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