Display posts from previous
Sort by

Please evaluate my crush

Post #1 made 12 years ago
by natept
Hello All,

I've been using a modified corona mill for a few batches now and settled on the below crush:
Image
Does this look about right? I've noticed my bag is draining a bit slower than it used to, but not by much. One beer (special bitter) that I just brewed about 4 weeks ago that I've brewed a lot before (with LHBS mill) has a bit of a grainy flavor that makes me think I might be grinding a bit too fine, but I'm not positive, pretty sure it will age out and other beers I've made after crushing with this mill did not have this flavor...It's only 4 weeks old now and it typically starts tasting right around 6 weeks so I'm hoping the flavor will fade -worst case I was thinking of adding some polyclar to finish clearing up the beer which may drop whatever is contributing that flavor.

Thanks for any input!

EDIT: I should add that I've been getting a little bit of husk material into the boil (bag issue - fixing it) - not sure if that would cause this grainy/almost tannic/astringent flavor though (it's probably been like a tablespoon or 2 of husk material max that I doesn't make it into the fermenter).
Last edited by natept on 08 Mar 2013, 21:29, edited 2 times in total.

Post #2 made 12 years ago
by PistolPatch
I am trying to participate in as few a threads as possible atm natept because I find so many questions so interesting. You got me on this one though :lol:.

[Be warned! A lot of the below is me thinking out loud and includes one thing I have never considered before. If you bother reading, you'll see I think I'm a bit wrong on that one thing :lol:.]

From the picture, I'm not sure, but I think I am seeing hollow husks. I would like to see how much flour there is. I suspect that the crush is still too fine but I am not sure.

But, let's forget all that and let's forget everything you have read about a crush and return to basics. Let's pretend a grain is like a can of soft drink (soda in the US?). It's nothing more than a vessel full of sugar.

How do you get the sugar out of soft drink? You simply open it at one point and you drink the sugar slowly.

Time will compensate for a coarse crush I think???

I've never seen it written anywhere else before but maybe more time in the mash will compensate for a coarse crush? Going back to a can of soda/soft drink, if you want to empty the contents of the soft drink in two seconds then smash it. If you are happy to not be so aggressive, then simply grab the ring-pull and pour the liquid out slowly.

Have you sliced a grain in half length-wise?

Grab a very sharp knife and cut a grain in half length-wise and then look at it with a magnifying glass. There is no 'sugar' in that grain that can't be readily accessed. It's a bit like cutting your can of soft drink in half. It's the perfect crush. Very good exposure to the sugar whilst minimising the exposure to the 'toxic' chemicals used in the can (tannins in the grain husk).

The Logic (To me anyway).

You only have to open the grain at a single point to release the sugars. If you were able to chop it in half length-wise, that would be the best but that is not going to happen.

Squashing it gently is another option but it's hard to do. Cracking the grain into pieces is the usual result. What I am trying to say here, poorly, is that two pieces is great - the vessel has been opened.

On reflection, I think my time theory above is wrong.

Thinking theoretically is good and fine and I can't see anything wrong with my time theory above but my wanderings there, at the end of the day, are not practical.

What really happens in a crush.

In a real crush, you run your grain through and, ideally, every grain would be broken in two or squashed a little. It never happens that way though. Some grains go through unbroken and others will get broken in three or four places. Or, every grain gets broken at the expense of some being pulverised.

It's all a compromise.

Great Topic!

This is a great topic natept :thumbs:. I'm not sure if my thoughts above have been useful but, even if they are, there are still so many things to consider and discuss here that will determine how to get the best compromise.

e.g. Roller knurling, roller diameter, roller speed, number of passes through the mill, pre-wetting the grain....

The Right Answer

Sometimes questions like this can get too theoretical and ignore the practicalities. The right answer here is that you would pre-wet your grains (no entirely sure on this to tell you the truth) and then run them through filters so that you could then run all grains of the same size through your mill the appropriate number of times (depending on knurling) and at the appropriate size gap. Repeat for all the other size grains. Ridiculous of course :P.

Obviously, it's all about finding the right compromise between 'opening' every grain versus 'smashing' the other grains.

In your pic natept, I see every grain broken. That is good but not if a lot of other grains have been smashed to flour. Wish I could see the crush with my own eyes - it's probably perfect!

:lol:
PP

P.S. I suppose one benefit of the above post is that maybe any reader that has got this far will realise that they shouldn't trust any post that says, 'run your mill at X rpm,' or at 'this gap,' or do this or do that.
Last edited by PistolPatch on 08 Mar 2013, 23:12, edited 2 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #3 made 12 years ago
by HbgBill
If what I have heard is correct.. one of the largest brewers in the US (Budweiser) crushes their grains VERY fine. It makes sense to me that the finer the crush (if you have the ability to work with such a fine crush) the quicker the hot liquids will be able to reach a maximum amount of starches for the enzymatic reactions to take place. If the liquid has to take time to 'reach down deep' into the pieces of husk, or even large pieces of endosperm, the more difficult it will be for the sugars to be released from that package. A picture I can understand in this regard is when we place hops, flower or pellet, into a bag and suspend it in the wort. All the hops get wet with the hot water.. but not all of the bittering, flavor, aroma will be released to the wort if we don't agitate the bag a bit. However, if you toss the pellets/flowers into the pot w/o a bag (husk/large endosperm chunks) the full potential of the material we are trying to access is readily/easily available for 'conversion' from pellet to wort. Another picture.. in my neck of the woods, we have a lot of adobe/clay in the ground. You can water it for a long period and the water will not penetrate easily. Even once wet, there is NO drainage as the soil is very compacted. If an amendment is added to break up the clay a bit.. the soil can accept new water for nutrient transfer.

I don't know if this makes sense to you.. but.. to me, the more surface area exposed to the liquor the better. Dealing with fine grist in a mash tun can be a real problem. It remains to be seen, with no experience, how that will translate to BIAB. My example has no background other than what I have heard about commercial breweries. I'll have to check with a couple of friends who are pro brewers at well respected craft breweries in my neighborhood. However, craft breweries may not use a fine grist. But, for me.. I don't know for sure. I'm a brewer without ANY BIAB experience.. yet :blush:

I hope this not only makes sense.. but has some degree of accuracy.

EDIT: I edited this for two reasons.. I brought up another question which was off topic.. and MAINLY because I mistakenly used the word flour instead of the words "fine crush".. yeh, I know the difference.. but, didn't say it correctly.. thanks for correcting me in the following notes :)
Last edited by HbgBill on 09 Mar 2013, 00:22, edited 7 times in total.
Bill
Hop Song Brewing-Santa Rosa, California

Post #4 made 12 years ago
by Aces high
Damn PP, thats a big answer :salute:

Natept i also use a corona mill, a porkert brand, one attached to a drill and its been working well for the last 3 years. I reckon my crush is pretty close to yours, just maybe a touch finer on the large grain pieces. But all grains have been broken, so i reckon thats pretty good

It works well for me, I usually get efficiencies (man im sure efficiencies is not spelt like that, but i've had numerous IPA's tonight) very similar to what the biabacus tells me i should get, so i think thats probably your best way of determining if the crush is working correctly

Post #5 made 12 years ago
by joshua
Good Day, I want to stay away from the "Crush".

NatePT, the grain appears to my Computer as Mostly "2 row pale Barley" or Wheat.

That can cause the "Grainey, Huskey" flavor, because the Ph was high (6-7ph), or the Mash Temperature was High(near 175F).

The Pale grains will to leave the mash water at the normal 7 ph.

That's My $0.02u.s.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #6 made 12 years ago
by BobBrews
+1 on what Joshua said! If you think your crush is not fine enough than let it soak (mash) a extra 15 minutes. If it's to fine (with flour) your wort may be a bit cloudy but that will clear out after fermentation!
tap 1 Raspberry wine
tap 2 Bourbon Barrel Porter
tap 3 Czech Pilsner
tap 4 Triple IPA 11% ABV
Pipeline: Mulled Cider 10% ABV

http://cheesestradamus.com/ Brewers challenge!
    • SVA Brewer With Over 100 Brews From United States of America

Post #7 made 12 years ago
by natept
Wow - thanks for the feedback so far. I think I need to read PP and HbgBill's replies a few more times!

Let me clarify - I'm happy with the efficiency I'm getting (both at 60 and 90 minutes) with this crush. I'm concerned by the grainy flavor in a recipe I'm familiar with (MO, 150L crystal, special roast) - which I mashed at 152 (for 60 mins) and mashed out at 168. I'm not worried about cloudy wort or anything I've been BIAB'ing long enough to know how clear my beers will get. I have not had this off flavor in hoppier beers that I've brewed lately that had a paler grist overall - which could mean a mash PH issue is the culprit (I'm no scientist though).

The picture above is 100% Marris Otter and it does not show as much flour as there is, but I don't think the amount of flour is excessive (not a whole lot more than when I crushed at the LHBS). I just took that photo the other day when brewing a Mild so thought I'd use that as an example of my crush since it's the same base grain as the Special Bitter.

Based on the replies here and other photos I've seen of BIAB'ers crushes I don't think the crush is the cause of the off-flavor.

The more I think about it, the more I think the off flavor comes from getting too much grain in the kettle or a mash PH issue. My bag's seam seems to be loosening a little bit and I think a bit of husk material is getting through there so I'm going to have the wife sew me up a new bag. Does it seem feasible that having say 2 tablespoons of husk material in the boil could contribute a grainy/astringent flavor or should I maybe focus more on mash PH? The beer is a bit hazy yet (as it normally is), but I'm thinking within that haze there could be some tannins that Polyclar can get to settle out so I'll give that a try most likely.

To further complicate things, I brewed a Mild the other day and mashed only with the Marris Otter and added the Chocolate and crystal malts when I started to raise the temp for mashout giving them about 20 minutes of contact time (as inspired by Hashie's thread http://www.biabrewer.info/viewtopic.php?f=49&t=246 ) so if it was a mash PH issue caused by darker grains than, in theory, I should not have this off-flavor in this batch, right (since I have not had this come up in paler 5-8 SRM beers with low lovibond malts in the mash)? There was, however, some husk material in the boil again.

EDIT: I should add that I use RO water and adjust with minerals/salts.

Target Profile for Mild (just brewed):
Ca 70, Mg 6, Na 32, SO4 123, Cl 101

Target Profile for Special Bitter (off-flavor):
Ca 114, Mg 24, Na 20, SO4 350, Cl 48
Last edited by natept on 09 Mar 2013, 02:57, edited 3 times in total.

Post #8 made 12 years ago
by BobBrews
natept,

A recent show about the taste of grain may shed light on this? Can't hurt? :peace:

March 7, 2013 - Zot's Specialty Grain Experiment
Zot O'Connor joins us to talk about his experiment in adding specialty grains to a finished beer to taste the effects.

Download the MP3 to listen later?
http://www.basicbrewing.com/index.php?page=radio

exact link to listen in on.
http://ec.libsyn.com/p/2/9/f/29f25f0da0 ... id=5439407
Last edited by BobBrews on 09 Mar 2013, 03:35, edited 2 times in total.
tap 1 Raspberry wine
tap 2 Bourbon Barrel Porter
tap 3 Czech Pilsner
tap 4 Triple IPA 11% ABV
Pipeline: Mulled Cider 10% ABV

http://cheesestradamus.com/ Brewers challenge!
    • SVA Brewer With Over 100 Brews From United States of America

Post #9 made 12 years ago
by joshua
Good Day, Dark Grains will lower the Ph 1-2 values lower, If mashed.
If used like Hashie said, there is very little change in Ph from the Water used at Mash-In.

The Flour from the Barley is mostly Starch, As is flour in general, so most all will convert!
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #10 made 12 years ago
by PistolPatch
natept wrote:The more I think about it, the more I think the off flavor comes from getting too much grain in the kettle or a mash PH issue.
These are two very good points but I think there are another two we can add here...

1. Check your sanitation - Often we brew twenty batches perfectly and then notice 'something' in the beer and start looking for answers in the wrong direction. Break down / pull apart all your brewing equipment and smell it. This problem may be the start of a big one.

2. Grain in kettle will expose you to tannin problems - There shouldn't be any grain in the kettle for the boil so check your bag's porosity. Grain husks etc contain tannins.

3. Too fine a crush will expose you to tannin problems - When we hear of some large breweries doing a fine crush*, that does not mean flour. Apart from the obvious lautering problems, if you pulverise a grain, you are also pulverising the lignin (woody) parts of the grain that contain tannins. You don't want to be boiling wood chips in your brew.

4. Poor mash pH (and high temps) increases tannin problems - Tannin problems can be avoided to an extent by limiting temperatures and controlling pH. Doing these things though will not completely prevent tannins.

We often hear that if your mash Ph is such and such or if you never exceed a certain 'magical' temperature, you will not have any tannin problems. Not true, especially if you have grains in the kettle or have a crush that exposes a large surface area of the husk to water.

The BIABrewer post here is not a long one but is probably a shorter, better read on the problems a fine crush can give you.

Bugger! I'm writing too much again :P,
PP

* From what I understand, a very fine crush in a commercial brewery would give about 30% flour. A normal crush about 20%. I assume they mean volume. One thing we can tell from these numbers is that a very fine crush does not mean 100% flour :P.
Last edited by PistolPatch on 09 Mar 2013, 18:33, edited 2 times in total.
If you have found the above or anything else of value on BIABrewer.info, consider supporting us by getting some BIPs!
    • SVA Brewer With Over 100 Brews From Australia

Post #11 made 12 years ago
by natept
Thanks for the responses. I brewed today with a new bag the wife sewed up - 0 grain in the kettle. Mash PH was in the acceptable range, will know in a few weeks if the grain was the culprit. If I still have issues I'll reread the responses a few more times and start dissecting my process further.

Cheers

Post #12 made 12 years ago
by wbosher
I pulverise my grains to powder in a coffee grinder. Never had an issue with cloudy beer (well once, but that was another reason entirely). I think with BIAB you can get away with a much finer crush than other methods, due to the bag acting as a filter, I guess that would also depend on how fine the weave is on your bag though.

Post #13 made 12 years ago
by natept
Figured I should post an update that since I replaced my bag I've been getting no visible husk material in the boil and the off flavor has not shown it's ugly head in the last 3 batches so I believe this mystery has been solved. Thank you all for the responses.
Post Reply

Return to “Intermediate Brewing”

Brewers Online

Brewers browsing this forum: No members and 36 guests

cron