Crusher Gap for BIAB
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I've varied anywhere from 0.025 all the way down to 0.010. Settled on 0.020 now for almost every batch. Never had astrigency, and I would guess the examples you've heard came from a pH issue or maybe even using a bag whose weave wasn't tight enough and some grain got into the boil.
MagicMatt
Brewmathemagician
I employ the 'malt conditioning' techniques described on Kai's website before milling my grain, and then mill at 0.55 mm (22 mil).
I do this for both normal AG and min-BIAB.
I do this for both normal AG and min-BIAB.
I do .025.
I have my BC set at 0.016" (0.4 mm) for BIAB. Keep your pH in control, and you won't have to worry about astringency.
Brew on
Brew on
Close the gap until the rollers are touching, then back off until they are not. Try milling. If the grain doesn't feed, open it up just enough so it does.
I do .25 for the simple fact that it's a single feeler gauge thickness. And I think BIAB should be foremost, easy.
Some of us still do 90 min, 60 min and a few have even experimented with mashing only 30 min (or less!).
Just stick with 90 min if you're conservative, and then slowly reduce mash times until you notice a difference.
I'm actually using a hybrid BIAB. I just bought the brew bag, for my mash tun. Been having issues with my fb, and was sick of having stuck sparges. FB also often lifted, having a ton of grains going under. All in all, I just wanted something easier so I ditched the fb in my mash tun and tossed the bag in there with a 3 piece ball valve.
This was also a solution to try step mashing straight on the burner. I could just toss the bag and grains in the kettle and do step mashes.
Used it for the first time, same crush, nothing changed in my BC, but i lost 8% effeciency, didn't change anything in my process except change the FB for the bag. I'm assuming it was the fact that I got annoyed at stirring as when I stirred the bag kept getting caught up and falling in. Next time I'll use bungee cords (didnt have any on hand) to hold it in place.
I thought, why not crush smaller now that I have bag. So I guess I'll start within the .020-25 area! Thanks everyone
This was also a solution to try step mashing straight on the burner. I could just toss the bag and grains in the kettle and do step mashes.
Used it for the first time, same crush, nothing changed in my BC, but i lost 8% effeciency, didn't change anything in my process except change the FB for the bag. I'm assuming it was the fact that I got annoyed at stirring as when I stirred the bag kept getting caught up and falling in. Next time I'll use bungee cords (didnt have any on hand) to hold it in place.
I thought, why not crush smaller now that I have bag. So I guess I'll start within the .020-25 area! Thanks everyone
Not sure what you mean but I assume you're basically making flour?
Psylocide
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I crush in a blender and yes, I make quite a bit of flour.
I'm fairly confident that tannin extraction is affected more by mash ph and temp. than it is by the crush (if at all).
30 minute is my standard. You should take gravity readings during the mash. That'll help tell you when you're done.
I typically do 60 minutes with my 0.016" crush. My most recent batch had an FG of 1.013, so I don't think I'm going too long and getting excessively high fermentability.
Brew on
I typically do 60 minutes with my 0.016" crush. My most recent batch had an FG of 1.013, so I don't think I'm going too long and getting excessively high fermentability.
Brew on
Isn't the argument for shorter mash time just about NOT wasting time? Mashing longer once the starch conversion has completed does not increase fermentabilitiy right, it's sort of just wasting time? Assuming you hold 152F for 60 minutes (with stirring intermittent) and the conversion is complete, then mashing at that temp (or lower) longer won't have much of an effect will it?
Mashing longer can increase fermentability, as long as there are polysaccharides that the amylase can munch on. There are polysaccharides that are small enough they won't trigger a positive iodine test, but can still be broken down into simpler sugars. Once everything has been reduced to mono, di, & tri-saccharides plus limit dextrines, additional time will not accomplish anything (as far as saccharification goes.)
You can track mash progress by monitoring the SG of the wort in the mash. Once it stops increasing, everything that can go into solution has done so. Although it might be possible to increase fermentability from that point with longer times. I don't know an easy way to actually monitor the molecular weight distribution of the wort (the sugar profile), which is what would really let you know what is going on.
The actual times required for mash completion will depend primarily on time and crush size. Finer crushes will complete faster than coarser crushes. Brewers who have low mash efficiencies often have incomplete conversions. This is why finer crushes improve their efficiency. They can also improve their efficiency by doing longer mashes in order to get complete conversion. In cases where a mash out increases efficiency, it is because the mash was incomplete, and the higher temps increase the conversion rate (until the amylase is denatured), and provide some additional mash time. There is nothing "magic" about a mash out w.r.t. efficiency. Homebrewers should be able to regularly achieve conversion efficiencies of 95% or greater. Conversion efficiency can be measured, and I describe how to do it here.
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