I am looking for some advice on what a good crush looks like, and whether it matters on my system. The opinions and pics online are all over the place on this.

Background: I am buying small-batch all-grain kits at my LHBS, and the grains come pre-crushed. I am pretty new to all-grain. I batch sparge in a two-gallon cooler, using a paint strainer bag instead of a false bottom or bazooka screen. The crushed grains have mostly whole husks separated from the kernel, what seems like a lot of flour, and about an 80-20 mix of broken kernels to whole kernels.

Does the crush, especially having a high flour ratio) make a difference if I am batch sparging? I don't have to worry about stuck sparges, but my wort is very cloudy. My finished beer is hazy.

I am getting absorbtion of around 0.25 gal./lb., which is around double the 0.13 gal./lb. rate I saw on this forum. (I calculate absorbtion as: [water into mash tun] - [volume of two runnings into boil kettle]. My mash tun has negligible dead space, and I run everything out on the second runnings.) Could the crush explain my higher-than-predicted absorbtion rate?

If it matters in answering my question, my efficiency into the fermenter is around 62-63% on my system using this crushed grain, I don't test pH or my water, I use bottled water, my strike water to grain ratio is 1.5 qts/lb., and I then add my sparge water based on how much more wort I need by measuring first runnings.

Edit: Correction, I misread my notes on what I am collecting. My absorbtion loss is a hair over one quart per two lbs. of grain, so that is squarely in the .125 gal./lb. that the experts tell us to expect.

  • do you use any kettle finings - whirlfloc/irish moss etc? These can help any flour that's made it into the kettle clump together, as well as proteins in the wort. – mdma Nov 11 '13 at 20:25
  • No, no finings. I have Whirlfloc, but the tablet is sized for 5-10 gallons, so I have not used it because my two five-gallon batches were very dark ales. I assume one Whirlfloc in a 1-2 gallon batch would be too much. I also ordered some isinglass (liquid), and hope 6 ml/gal. will help. Does cold crashing work with suspended starch, or only on yeast? – Chino Brews Nov 12 '13 at 4:28

A good crush should keep the grain husks intact, since they will then filter out the flour and provide an efficient lauter. I also crush reasonably finely, which does produce some flour, but as long as the husks are intact you're good. I have a 3 roller mill - the sales pitch was that it doesn't pulverize the husks as much as a 2 roller. I've not used a 2 roller, so can't comment on the difference, but I do see the husks clearly in the grist and get very clear wort after 90 mins of mash recirculation.

  • Thanks. Does the husks' filtering action matter if I am batch sparging through a paint strainer bag, and running off wort as fast as the tun's spigot allows (after about a quart of vorlaufing)? – Chino Brews Nov 12 '13 at 4:25
  • It may have a little affect but if the mash isn't being continually vorlaufed then it doesn't really matter. But like Denny says, I doubt the cloudiness is from flour. If it's starch haze, are you sure you are getting complete conversion? An iodine test can tell you that. – mdma Nov 12 '13 at 12:25
  • 2
    More reliable than an iodine test....braukaiser.com/wiki/… – Denny Conn Nov 12 '13 at 16:56
  • A very interesting read Denny, but I don't see how it's more reliable than an iodine test - or that it can even replace an iodine test. A precondition to using the formula is that the mash is complete (see first paragraph) - and that is what we're trying to find out. Using just the formula alone, weight of solubilized but unconverted starches will throw off the calculation. – mdma Nov 12 '13 at 19:19

Clarity of wort has no bearing on the clarity of the finished beer. Beer clarity is much more dependent on things like proper pH and mash conversion an d a large amount of flour should have no effect. My crush is very fine with a large amount of flour and my efficiency ranges from 80-85%. Based on that, it's difficult to believe your wort loss is solely due to absorption. Is there any dead space in your mash tun that could account for it?

  • I have virtually zero wort loss, if you can believe it, because I can lift the grain bag slightly, tie it to my cooler mash tun handle, and then tip the tun to get almost every drop. Your answer made me double check my notes on absorbtion loss, and I hd to correct it because I am in the right range. Thanks for the info. It looks like the flour should not concern me, but I have quite a lot to learn on pH and getting good conversion. – Chino Brews Nov 12 '13 at 4:22

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