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HI:
I'm interested to find out what type of analysis
some of you do on spent grain.
Txs
Fred
I'm interested to find out what type of analysis
some of you do on spent grain.
Txs
Fred
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I always start with a check around the outside edge of the top of the grist looking for "old widows" (uncrushed grains), then look at how much proteinaceous material (that grey gluggy stuff) is sitting on the top of the bed. Both these points are indicators of the crush and possibly (hopefully rarely!) the quality of modification of the malt.
When opening the manway to remove the spent grist (only really works on side mounted manways), take a hard look at the layering of the grist. There should be a strata of husk rich grist immediately above the plate merging into a more general pattern of the spent grist as the depth increases. If there has been a problem with the runoff, sometimes you can find a clue here where there may be stratas of proteinaceous material that would normally be on top of the bed indicating channeling, or possibly a liquor/grist ratio that may be a little on the low side. You may also see clumps of grist that balled up during mashin and never fully broke down.
I also take some of the spent grist and look at it very closely for any starch chunks, badly crushed grains and poorly hydrolysed starch. This can be caused by the crush being too course, mashing times too short and general mash chemistry being out of kilter. It is usually always more than one factor though.
Finally I like to do an Iodine test on the spent grist - especially when doing the first brews on a new system. Take a couple of spoons of spent grist and place in a 50ml beaker. Rinse well with tap water to remove any retained wort, adding some water to make a loose slurry. Drop in some Iodine test solution - quantity is not that important. You will mostly get no reaction. Now mash the spent grist with you finger adding a little more Iodine. You may be surprised at the amount of starch that is still present. While it is almost impossible to convert all the starches in mashing, if you get a immediate black" reaction with the Iodine, then you have way too much starch left in the grist.
Wes
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