Fine versus Normal Crush Experiment

[MODNOTE: This thread originally began here but deserves it's own thread. mally feel free to write an introduction below.]

OK, so this thread has been excised from a previous one and so may seem a little disjointed at first. However....

The basic idea was that a fine crushed grain (or even pulverised/blitzed) could give you good quality wort, no compromise of quality, but in a much reduced mash time.
I set up a side by side experiment to compare pulverised grain to shop bought pre-ground grain.

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There are currently 3 pages (65 posts) in this thread (Oct 2014), for those who want to skip the read, this is what I feel is the current state of affairs.
The results were interesting but there is no conclusion, and possibly left us with more questions! The best answer/summary for me is as follows;

Let's Get Back on Track

What We Do Know

1. Laboratory Tests for extract potential (Congress Mash) show that there is only approximately 1.0% gain in extract potential between a fine and coarse grind. Considering that your kettle efficiency on an average brew might be about 80% then the difference will be about 0.8%.

Read: This and This. Hard stuff to get your head around.

2. We know from collecting many brewer's numbers, that kettle efficiency rises over time for many malts. So, doing less than a 90 minute mash can sometimes cause a significant loss in kettle efficiency. In some malts though, very little difference will be noted between say 60 and 90 minutes.

What We Don't Know

1. Does a fine grind significantly speed up extraction?

2. More importantly, does a fine grind significantly increase 'Kettle to Fermentor Loss (KFL)' and/or 'Fermentor to Packaging Loss (FPL)'? If so, it will also be reducing the amount of beer you end up with at the end of the day.

3. Does a short mash time (regardless of grind) affect any parameters such as attenuation?

4. More importantly, does a short mash time (regardless of grind) affect quality?

I think that summarises it ,
PP

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The original posts are as below:......

• • SVA Brewer With Over 100 Brews From Great Britain
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...I am certainly interested in a little experiment though, just to see one way or another.
i was thinking of pulverising the grain in a blender, then sieving the flour to see if I can remove any of the husk material (chaff).

Small sample, something like 250g, to make a 1L VIF (not wasting 5Kg), mash at 65C, take gravity measurements at 1 minute intervals until no change.
Normal fermentation, see what the hell it tastes like.

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Go for it. That would be great mally but...

Don't separate the husks. Pulverise everything and add the whole lot - that is what they are doing. This will avoid any weight comparison issues assuming you can do a side by side (which you'd need to do) and will also help show if there is a tannin issue.

The experiment would not only need to be a side by side one but would have to be repeated a few times on different styles.

Never easy eh?

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Just to play devils advocate here

What if there is some truth in fine crushing? What parameters are required for it to work/not work (if any)?

I can easily believe that powdered malt converts much quicker. In fact I wrote a few years back that you could theoretically brew with no bag if you could somehow de-husk the barley and just add to your kettle the endosperm & embryo (separating pericarp, testa, aleurone) etc. Though I guess it cannot be done easily (or inexpensively).
The question for me though is, what does the resulting beer taste like? Is it repeatable, robust, suitable for all styles, and what other effects are there? trub etc.

I do plan to test this myself soon (no promises here) but this is what I propose;
side by side experiment where I use the same ingredients at the same time under the same conditions.
One batch of the malt is used as is supplied by the LHBS; pre-crushed.
The other batch is blitzed in a food processor into a fine powder.
Both are mashed & boiled at the same time.
During the mash, take regular gravity readings to plot progress (of both). I think 1 minute intervals will be too difficult to achieve, as I will have to closely monitor temps as well.

Here is the recipe

FEEL MY CRUSH

Brewer: Mally
Style: (OGK) “only god knows”

ABV: 4.1% (assumes any priming sugar used is diluted.)

Original Gravity (OG): 1.040
IBU's (Tinseth): 35
Bitterness to Gravity Ratio: 0.87
Colour: 6.3 EBC = 3.2 SRM

Kettle Efficiency (as in EIB and EAW): 94.5 %
Efficiency into Fermentor (EIF): 81 %

Mash: 90 mins at 66 C, Boil: 60 min, Ferment: 7 days at 18 C = 64.4 F

Total Water Needed (TWN): 3.13 L
Volume into Boil (VIB): 3.15 L @ 1.015
Volume of Ambient Wort (VAW): 1.17 L @ 1.04
Volume into Fermentor (VIF): 1 L @ 1.04
Volume into Packaging (VIP): 0.93 L @ 1.01 attenuation of 75 %

100% PILSNER MALT (5 EBC = 2.5 SRM) 167 grams

33.3 IBU CLUSTER Pellets (7.3%AA) 1.9 grams at 60 mins
1.7 IBU CLUSTER Pellets (7.3%AA) 2.3 grams at 1 mins

Mash Type: Pure BIAB (Full-Volume Mash): for 90 mins at 66 C = 150.8 F

Strike Water Needed (SWN): 3.19 L at 66.5 C
Mashout for 10 mins at 78 C

Hopsock Used: n
Chilling Method: NATURAL/AIR COOL

Fermentation: St Austell for 7 days at 18 C = 64.4 F

Secondary Used: n
Crash-Chilled: n
Filtered: n
Req. Volumes of CO2: 2.5
Serving Temp: 6 C = 42.8 F
Condition for 30 days.
Consume within 12 months.

Any comments, theories, suggestions, or corrections? please feel free to contribute

• • SVA Brewer With Over 100 Brews From Great Britain
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Thanks Joshua, I may get around to looking into that (I noticed your new thread too)

However for this grain crush experiment; I have only gone and done it!
There are some good and bad points to it but I think that goes with the territory with experiments.

I decided to go for 150g Weyermann Pilsner malt in 2L water (TWN), one as normal, one "blitzed" in a blender, more info to follow after some pics;

NORMAL CRUSH.jpg

150g of normal crushed grain as is from the LHBS.

BLENDER.jpg

150g of normal grain after approx 30 seconds in a blender

BLITZED.jpg

The same grain in a tub, just to show that I lost 1g in the transfer.

TWN.jpg

Scales are "tared" with empty pan(s) and filled with 2Kg water (2L nominal).

DUAL MASH.jpg

Both pans are brought up to mashing temps (approx 66C) bags located and grain tipped in. Mash is at 65C after dough in.
The first interesting thing I noticed was that the "blitzed" grain formed doughballs very easily. No big problem though, just took a little longer to thoroughly mix in.

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Well, I just decanted the wort off the trub and took gravity readings and piched yeast.
normal = 1.038
blized = 1.033

Must be a discrepancy with volumes/trub here.
In hindsight I should have made a better effort to measure volumes with gravity, but I just wanted to get the yeast pitched ASAP.

I squeezed the remining wort from the dropper into my mouth to see if i can detect any odd flavours in the wort.
Normal - seemed quite bitter (which is something I normally find anyway).
Blitzed - I was readying myself for a huge tannin explosion, but , actually seemed a little smoother, but that could be due to the weaker gravity or the fact I had just previously been exposed to bitterness.
Maybe the tannin is more subtle (if it even exists), and can be more easily detected in carbonated & conditioned beer?

Next is to see how they ferment. BTW, I pitched a teaspoon of very thick slurry into each, so even if under/overpitched, they have the same rate.

• • SVA Brewer With Over 100 Brews From Great Britain
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mally, I was going to write here yesterday and then saw you were into the experiment already. Nice job mally .

I'm wondering if you had the same volumes going int the boil? In other words, did the fine crush retain more liquor? Or do you think the volume loss was from more kettle trub?

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Joshua, thanks for that, but your comment still confuses me

I agree that the grain will hold exactly the same amount of water regardless of grind. In fact you could argue the finer ground holds slightly more as there will be more surface area? However, the fact that there is less material left behind after mashing means that either more material (including liquid) has left the bag, or it is the same and more compacted.


BTW
The fermentation of the samples is well underway; here is a pic of them 12 hours in.

12 hours ferm.jpg

24 hours in and it could be nearly done.

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Like your signature Josh

mally

Surprised there weren't more comments on your graph in post #51. I thought that was excellent . I've never seen anyone do a side by side on this. Sure, a few more replications would be needed but it's already very interesting. Side by sides are the most valuable of experiments.

[This is also one case where refractors readings are far more practical than hydrometer ones. If you took hydro ones, you'd have to let them cool in the freezer for 20 or 30 minutes and during that time, the mash is still continuing in some way though it might be small.]

Let's say that your results were repeated several times on side by sides, then there really is no advantage on a fine grind. Even if you wanted to do a twenty minute mash, the grinds are almost even. The real question is not one of crush size but more one of what does extra mash time add to beer quality apart from some extra efficiency into boil? Lylo has already mentioned attenuation and I know I have read other stuff but have no time to rack my memory banks or research atm.

Anyone else got some links or references?

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The BIABacus also has a temperature correction tool Josh but, unlike other correction tools, it will warn you when you are trying to correct at too high a temperature (the further you are away from the ideal temperature, the less accurate the correction). Also many hydrometers will crack at high temperatures (over 50 C / 122 F) and you can be heading into snapping territory) .

Another interesting thing here is the over-valuation of time given to making sweet liquor. For example, trying to remove all the husk from the grain and then crush it is going to be a lot of work. Just doing a normal crush and waiting for 90 minutes (or 60 minutes if you want to sacrifice a little efficiency etc) is not a big deal especially when compared to the time that goes into the other parts of brewing, the main one being cleaning .

As mentioned above, if mally's experiment can be duplicated, at 60 mins there is no advantage or disadvantage, kettle-efficiency wise between blitzed and normal crush so the question becomes all about quality versus mash length.

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Got to race but you'll find the link and the BIABacus temp correction are within a gravity point of each other (it's a simple density formula) but the terminology used in the BIABacus is a lot clearer. Hydros are calibrated to a certain temperature and this is the temperature that you need to type in. Regardless, as I mentioned above, large temperature adjustment correction is not great practice .

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I'm glad we have some discussion at least

I have just tipped the samples into 2 bottles each, sediment and all.
Probably about 400ml in each bottle.

I will crash chill these in a few days for a couple of weeks and see what we have.
I must remember to take a gravity reading though. I have not primed them, I want to keep things as "unaltered" as possible.

• • SVA Brewer With Over 100 Brews From Great Britain
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You've got me worried now mally .

400ml in what size bottle? Why crash-chilling for two weeks? (Two/three days in a bottle will be fine).

From memory, you don't have a CO2 bottle but if you did, you could force-carb them but, in this case, I think tasting them uncarbonated would be fine. i.e, get the final gravity reading (wet and shake the hydrometer and the jar first) and then do a taste test.

Great job you are doing ,
PP

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You are way ahead of me mate - good on you .

Oh, hold on, when to get the gravity reading? You'll have to "flatten" them to get a proper FG and you'll need 250 mls to do that with a hydro. Bugger that! Maybe use your refractometer to see if there is some difference. If so, take a couple of small samples to double-check?

At this stage of the game, I think taste is what matters (and about three other brewers, to put their hand up to spend the time you have to see if they can replicate your results.)


PP

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OK, so here is the experiment update;

Just to recap...

The recipe of 100% pilsner malt & cascade hops was a reasonable choice as there should be nowhere for flavours to hide. The hop additions were light/minimal at 1g/L for both (bittering & flameout).

Normal - O.G. 9.5 Bx (1.037), F.G. 4.3 Bx (1.008), 3.6% ABV
Blitzed - O.G. 8.2 Bx (1.031), F.G. 3.9 Bx (1.008), 3.0% ABV
All measurements carried out with a refractometer, F.G. data obtained by using the Sean Terrill calculator.

blitzed exp pic.jpg

Blitzed is on the left, normal on the right.

The difference in taste was almost imperceptable. In fact, the difference between them was probably due only to the ABV?

There were no off flavours in either of them. At a push I would say the normal one had more body & mouthfeel.
They both finished out at the same gravity which is a little odd? attenuation(s) of 78% & 74%

What this experiment tells me is that (n=1, so be careful)! not only is further investigation required, but can be done so without the fear of potentially making undrinkable beer.
The trub issue is still a little strange, it didn't seem to be excessive, but was very powdery.

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