Iodine Test / Ph test

Discussion in 'General Brewing Discussions' started by MrBIP, Nov 9, 2013.

  1. MrBIP

    MrBIP Active Member

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    Continuing my research and planning for first all grain next weekend, this morning I'm reading about the iodine test to check for completed conversion of starches to sugars. Seems to be some mixed opinion on whether or not the test is worthwhile. So do you do this test? Why or why not? Seems simple enough and I'm thinking that perhaps when I'm first starting, it might be a good idea to be sure what I'm doing is working.

    Also wondering if I should pick up some pH test strips? But, since I do not know my water chemistry or have anything to adjust it, if the pH of my mash if off, there's nothing I'll be able to do about it. It would only be information at this point. Worth a few bucks or not?


    Thanks,
    MrBIP
    (one of these days perhaps I'll be one of the guys answering the questions instead of asking :) )
     
  2. grainy one

    grainy one New Member

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    Hi MR. bip. I did about 10 batches of all grain before I got ph. strips ,wish I would of got them sooner.
    I'm just now starting to change my water to get different tastes in my beer and its vary hard to make adjustments with out good info. I suggest you get water profile at least ,so you know where your starting from .
    I would not let it stop me from brewing though. Got to make mistakes in order to learn from them. Good luck.
     
  3. Nosybear

    Nosybear Well-Known Member

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    On the iodine test, I'd advise you keep doing it until you're sure you no longer need to or, importantly, any time you mash below about 148° - conversion is slower so you might need to check it. Eventually you'll come to know what a converted wort looks like, clear and bright, and won't need to test. As to the pH strips, might be a little obsessive given you're working on your first all-grain batches. I use them intermittently - citing the science of brewing, as long as your water isn't too hard and you have enough calcium (more than about 40 ppm), your mash should regulate its pH automatically, the exception might be for a beer with no dark malts. And you can get a cheap meter on Amazon for a little more than a bottle of strips. But here's my take: You're in your first all-grain batch. If you've brewed successfully with your water in the past, don't worry about it. You have enough process changes to worry about. Obsess over temperatures - the relative effect of a degree or two of mash temperature are far more important than the relative effect of a point or two of pH or a few ppm of some ion. We brewed beer long before we knew what ions or pH was, Ninkasi be praised. It'll still work today with our much improved ingredients, sanitation solutions and refrigeration.
     
  4. MrBIP

    MrBIP Active Member

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    Thanks, that's kinda where my thoughts were at. Checking pH would be informational only since I have no method of correcting and my extract brews have been good (and getting better). Maybe I'll look for one of those cheap amazon testers just to satisfy my curiosity at some point.

    On temps, the final test I run on my cooler mash tun will be to put 5 gallons on water in at some elevated temp And check it every 15 minutes for drop. I know it's not the same thing, but maybe at least give me an idea.

    The greatest unknown will be efficiency. I'm formulating at 65%, but of course have no idea, so plan to take gravity sample at multiple stages. No refractometer yet, so that will be a little messy.
     
  5. Nosybear

    Nosybear Well-Known Member

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    You'd be surprised how accurate your water test is - the grains hold far less heat than the water. Good idea!
     
  6. sbaclimber

    sbaclimber Well-Known Member

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    When I started all-grain brewing, I did the iodine and ph tests the first few batches. More for shits-and-giggles but also to make absolutely sure I wasn't making any catastrophic mistakes. Didn't detect any problems, and now have a bottle of iodine that I occasionally use to disinfect wounds... :lol:
    As long as you know what your water chemistry is and control your mash temps, I haven't found any reason to use iodine. pH can be interesting for improving efficiency, but that is also relative to water chemistry. (I get 70% brewhouse w/o altering pH)
     
  7. MrBIP

    MrBIP Active Member

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    Well, I ran two tests. First one at a lower temp lost 1 degree in an hour. Second test at higher temp, with oxy clean, lost 4 degrees. Checked both at 30 minutes, so certainly that had a slight affect. Bumped the strike temp on my first recipe by 2 degrees, which should just put me at the top of the range to start (I'm shooting for 150-152 on this).

    At LHBS was told never had a failed iodine test, but good to check, worse case scenario is drain the tun, reheat the unfinished product to strike, and go again.... so there's a plan if it does happen to go awry, but I'm doubting it will. RDWHAHB ... all jacked up, can't wait until this weekend.
     
  8. Nosybear

    Nosybear Well-Known Member

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    I use my 10-gallon mash tun as follows: Aim for one degree high at strike. Temp drifts by about 1° every 15 minutes. So I add a quart of boiling water at 30 mins, which brings the temp up 2° (you can use the mash calculator to see how much boiling water at your elevation it takes to up the temp by 2° for a specific quantity of grain and water). Using this procedure, I stay within about a degree of my desired mash temp. It also illustrates controlling a level, in this case temperature, procedurally rather than trying to keep it exact. At homebrew scale, the variance of a degree either way is more than close enough.
     
  9. The Brew Mentor

    The Brew Mentor Well-Known Member

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    Here are a couple of tips;

    Preheat your mash tun. Simply put your measured strike water in about 10° hotter than your desired strike temperature. Close up the Tun and let it rest and absorb the heat for about 5 minutes or so. Then open the Tun and stir the water until it drops to your strike temperature. Then mash in.

    Keep your Tun in a warm place or wrap it with a blanket. I used to set up outside but found it better to mash inside the house when it's cold outside. This will prevent major heat losses.

    Take a look at different strike water calculators. I have the most success using the one on BeerSmith. I will also use the formula from John Palmer's How to Brew. Not a knock on Larry's, but I've had success with those and when I used the one here, I was off quite a bit. I'm not sure how it's calculating heat losses, but it hasn't worked for me.

    If you're within 2°, just leave it alone and take good notes for next time. Have some boiling and or cold water ready if you're way off and add a little at a time to adjust. It's very difficult to get the Tun to adjust exactly to where you want it.

    Don't mess with it! Your mash is fine. The enzymes know what they're doing. I hear from people all the time that they stir every 10 minutes. I find this completely unnecessary. You may get a little better efficiency but you also will have much greater temperature drops and more difficulty maintaining the temperature. I loose about 1-2° over an hour. This is very acceptable and also repeatable! It's also more enjoyable!

    A grist with more flaked products or at a lower mash temperature will take longer to convert. If I'm making a light lager or a Beer with high amounts of flaked adjuncts, I usually plan for a 90 minute mash. I do check those mashes with Iodine and find it very accurate in determining the conversion.

    Have fun and take good notes!

    Brian
     
  10. MrBIP

    MrBIP Active Member

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    ^ Stirring every 10 minutes doesn't seem like a good idea .. never even considered that. Temp certainly most important.

    I like your method of pre-heating. I had planned to pre-heat, but was going to pre-heat dump and put strike water in; what you describe certainly makes sense.

    I've been using this calculator: http://www.brew365.com/mash_sparge_water_calculator.php ... my last half dozen extracts I was able to nail the temp for the my steeping grains (in larger quantities that one would normally steep) and was also able to nail the final volume to fermentor exact or within a couple of quarts.
     
  11. Ozarks Mountain Brew

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    one thing Ive learned as far as ph is most people are worried about the mash ph and always shooting for around 5.2 or so but what you can run into according to my LBS is the sparge water ph, some waters are around 7 to 9 ph the mash brings the ph down correct but sparging with 7 to 9 ph water can lead to tannins in your wart

    sorry wrong forum lol
     
  12. TheZel66

    TheZel66 Member

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    I've always done an iodine test... probably not needed anymore, more like a security blanket.. That is unless you're trying to see how fast you can get conversion. remember... black means starch, clear means sugar.
     
  13. Ozarks Mountain Brew

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    I can't even get iodine here, stupid druggies use it to make brain killing drugs
     
  14. grainy one

    grainy one New Member

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    so that's why I can not find any either. Its really to bad a few have to ruin it for the rest.
     
  15. Head First

    Head First Well-Known Member

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    Remember you're homebrewers! Be inovative. Iostar works also. It starts dark but if it goes black or purple-bluish then wait a little longer.
     

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