Mash thickness and volume

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NormandieStill
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Mash thickness and volume

Post by NormandieStill »

So I had an epiphany of sorts this morning. A few days ago I stripped my first batch of HBB, but having missed a line in my notes, I had mashed in with too much water and ended up with an SG of 1.046 instead of the 1.068 I was targetting. I stripped down to 20% in the pot which left me with about 5L of low wines. Which corresponds with the predictions from the pot still purity calculator.

Planning the next batch I decided that I need to mash in with 19L instead of 25L* which would get me closer to my target. Notice that I'm scaling the water, not the grains. Running those values through the calculator though produces around 5L of low wines at 20%. Which suggests (and this makes sense) that the volume of low wines depends on the grains and not on the overall volume of wash run through the still. That is to say that 5.25kg of grains mashed in to produce 30L of clear wash at the end would still produce 5L of low wines.

So... I would assume that higher dilutions will lead to a flavour loss (assuming the flavour is just carrying over with the water and not being fractionated by the distilling process), and at some point there's probably an efficiency loss when mashing from over-diluting the grains. But is the rule of thumb grain / water ratio often used on the forum a sweet spot for flavour carry-over or just the maximum manageable thickness of mash?

* I understand that I could also increase the grains, but I have enough melano for 2 more batches at this size and don't need enough other grains to justify the shipping cost of buying some more right now.
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Re: Mash thickness and volume

Post by Demy »

I think the water / grain relationship is indicative and is a compromise between viscosity / volume of the mash. I personally prefer a slightly diluted mash instead of too much "solid" and I believe that even the efficiency is helped (within certain limits), also depends on the method used and from the available equipment.
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Re: Mash thickness and volume

Post by 8Ball »

I hit 1.070 pretty consistently using a 2.25#/G mash ratio. Ferment on grain, squeeze, strip & spirit.
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Re: Mash thickness and volume

Post by NormandieStill »

I have a volume problem in that my mash tun is a 30L keg and my fermenters are 32L so in order to keep some headspace I really don't want to push more than about 28L total volume. I did find that both the mash and the squeeze post-ferment were easier with this "lite" mash. I'm just wondering if anyone has experimented with this and if there's a noticeable flavour difference.
8Ball wrote: Mon Oct 25, 2021 9:31 am I hit 1.070 pretty consistently using a 2.25#/G mash ratio.
2.25#/G is 270g/litre. I was at 230g/litre. My proposed 19 litre mash would put me pretty much on the mark for 270g/litre.

I guess I'll try mashing in thicker on the next batch and depending on how that goes, I'll adjust again for the 3rd batch.
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Re: Mash thickness and volume

Post by 8Ball »

NormandieStill wrote: Mon Oct 25, 2021 10:08 am
I guess I'll try mashing in thicker on the next batch and depending on how that goes, I'll adjust again for the 3rd batch.
Just a thought: maybe mash in with 1G/3.8L less water than your mash bill requires. Then add everything to your fermenter so you are under your max fill mark — then top off with your yeast starter and/or water?
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Re: Mash thickness and volume

Post by still_stirrin »

Another thing to consider (from my early years brewing all grain beers) is that the enzymes (alpha and beta amylase) behave and perform differently in different “densities” of the mash, not just temperature related. Beta amylase prefers a little “stiffer” mash consistency, while the alpha amylase like things nice and “fluid-like”. This is why upward “step infusions” are used in breweries and by homebrewers. It allows the brewer to control the ratio of beta and alpha enzymes in the mash to create the flavor and fermentability profile desired for the particular beer style.

While the enzyme development is one consideration, realize too that a “thinner” mash will allow for a quicker conversion of the starches due to the hydrated exposure of the grains. Crush consistency also affects this as well. And because timing is a consideration on brew day, often times some of the conversion process is truncated due to impatience. Liquid mashes seem to work quicker in this regard and therefore improve total extraction rates. But, it will affect the ratio of fermentable to non-fermentable sugars extracted. So, YMMV.

As a rule, I tend to “dough-in” with 1-1/4 to 1-1/2 quarts per pound of grist (grains). Then, I’ll infuse upward through a “protein rest” (critical for wheat mashes), to the beta rest (fermentable sugar production). And finally, I’ll infuse upward to the final alpha rest if I want to hold some non-fermentable sugars in the wort. Usually by the 2nd infusion, my mash consistency is around 2-1/4 to 2-1/2 quarts per pound. I’ve got more than a few awards (AHA) with this process, so it does work.

The secret is: practice. Mash over and over and over long enough and you’ll hone your process and products. Afterall, the highlight of the brewday is the product.
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Re: Mash thickness and volume

Post by LordL »

We have succeeded quite well with very thick mashes. Make a thick porridge and let it stand from 65C dropping to 62C for about an hour. Stir every 10 mins. Empty the water, squeeze, in with new water to hit 65C again, mash for half an hour or until it drops to 61C. Repeat with a last sparge at higher temp. In this way we got 45 l in the fermenter on 14 kgs of malt. SG 1.080
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Re: Mash thickness and volume

Post by NormandieStill »

OK. Thanks for that, some interesting stuff to think about.

LordL, you seem to be double mashing (not just sparging). Do you know your SG for each mash separately? Interesting way of pushing higher batch volumes from a smaller mash tun. Your recipe would give me 2 decent stripping runs per "mash" and so two mashes would nicely fill my 30L boiler for the spirit run.

still_stirrin: As always your depth of knowledge never ceases to amaze. I've only just started AG brewing (got one very drinkable oatmeal stout under my belt), but I'm clearly going to end up having to get my head around the subtleties of beer mashes (compared to the sledgehammer approach that seems common for distilling)
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Re: Mash thickness and volume

Post by LordL »

@normandie
Yes, you could call it a mash -sparge maybe. The idea is to convert as much sugar as possible at the same time you want to dissolve as much sugars as possible to get into the fermenter. We try to push our limitations in equipment, for our 5l cask. This is not going to give us quite the 5l cask strength we want, but should be pretty close!
SG is from the total, after mixing and distribution between fermenters. Should remember to measure separate next time!
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Re: Mash thickness and volume

Post by NormandieStill »

I'd be very interested to know your individual SGs before combining. A quick browse with an online brew calculator puts your efficiency at 83%. Which seems quite respectable. I'm not sure how that compares to on-grain ferments (where a slower conversion of any remaining starch can be taking place in parallel with the ferment) but it seems worth a go. I'll add it to my experiment list (next mashing experiment is for a partial boil AG beer to get around the fact that my only stockpot is 18L and I'm trying to cook up a 25L batch. This will get me the chance to see what a porridge mash is like.
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Re: Mash thickness and volume

Post by tiramisu »

I hope I remember to check your outcome... posting so I do.
It may be that you get more flavor with more water than less.

Same, amount of abv but the less thick mash may extract more water-soluble thingies out of the mash.
All else being equal (and it never is) flavor difference in the cuts would be the proof point.
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Re: Mash thickness and volume

Post by LordL »

NormandieStill wrote: Wed Oct 27, 2021 11:30 am I'd be very interested to know your individual SGs before combining. A quick browse with an online brew calculator puts your efficiency at 83%. Which seems quite respectable. I'm not sure how that compares to on-grain ferments (where a slower conversion of any remaining starch can be taking place in parallel with the ferment) but it seems worth a go. I'll add it to my experiment list (next mashing experiment is for a partial boil AG beer to get around the fact that my only stockpot is 18L and I'm trying to cook up a 25L batch. This will get me the chance to see what a porridge mash is like.
I think it's something worth experimenting further on, for us anyway. And yes, expected efficiency around 80% sounds about right. It's the only way forward for us, if we don't want to ferment on the grain, which we did partially for our last batch, which was a bourbon. This will be a try on a peated scotch though. Trying to keep it as close as we can, stripping down to 0,1% and try to force the smokyness into the hearts.
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Re: Mash thickness and volume

Post by NormandieStill »

Update as promised. For my second batch of HBB I mashed in with 19L of water this time. And now I finally understand what everyone was going on about when they talk about making porridge with corn. After about 2 hours of soaking time I could stand my mash stirrer up in it. And it thinned almost instantly when the temp had dropped to 74C and I added the malts. I got an OG of 1.063 so a little lower than I'd hoped for.

It's now fermenting and when it's finished and I've stripped it, I'll do the ill-advised and taste the two batches of low-wines to see what the flavour difference is like.
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Re: Mash thickness and volume

Post by Ben »

For barley I go 1.25qt/lb. But with the really sticky mashes of corn I go 2.33 for the gel rest, then don't add any water when I cool and add the grain. I don't really have a choice because water boils at 203 here, and if I am going to hit gel temps I have to use this much water. The side effect is it gets me up in efficiency. I fly sparge and boil to maximize efficiency, I use the boil just to consolidate what I am pulling so I can fit it in the fermenters and get a little more head room in the still.

As long as you aren't over stripping the grain (pH starts to rise at some point and you get astringincy) I am not sure the water volumes and ratios make too much of an impact.
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Re: Mash thickness and volume

Post by Ben »

For barley I go 1.25qt/lb. But with the really sticky mashes of corn I go 2.5 for the gel rest, then don't add any water when I add the grain. I don't really have a choice because water boils at 203 here, and if I am going to hit gel temps I have to use this much water. The side effect is it gets me up in efficiency (as much as 93%). I fly sparge and boil to maximize efficiency, I use the boil just to consolidate what I am pulling so I can fit it in the fermenters and get a little more head room in the still, IE boil until it is around 1.070. Really though, feed corn is ≈$0.24/lb... its not that costly to up your corn by 10% to bring up your gravity if you have a struggle.

As long as you aren't over stripping the grain (pH starts to rise at some point and you get astringincy) I am not sure the water volumes and ratios make too much of an impact (within reason).

If you have the room in your fermenter and still kettle why would you not mash thinner? Makes almost every aspect of the mash a lot easier/faster. If you are fermenting on the grain it means you have a lower concentration of alcohol left in the grain when your done, if you sparge it goes faster, lower gravity is going to be easier on the yeast. If you are concerned about enzyme density we have great liquid and powdered enzyme options available to us that will correct that.

Seems to have lot of upside and very little downside?
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Re: Mash thickness and volume

Post by NormandieStill »

Ben wrote: Sun Nov 14, 2021 7:09 am As long as you aren't over stripping the grain (pH starts to rise at some point and you get astringincy) I am not sure the water volumes and ratios make too much of an impact (within reason).

If you have the room in your fermenter and still kettle why would you not mash thinner? Makes almost every aspect of the mash a lot easier/faster. If you are fermenting on the grain it means you have a lower concentration of alcohol left in the grain when your done, if you sparge it goes faster, lower gravity is going to be easier on the yeast. If you are concerned about enzyme density we have great liquid and powdered enzyme options available to us that will correct that.

Seems to have lot of upside and very little downside?
This was sort of what I was thinking, but without years of brewing background to draw from. In a few weeks time, when I've stripped the second wash, I'll be able to do a side-by-side comparison with the first to see what difference (if any) there is in the flavour of the low wines. If there's little or no difference, then I'll be mashing thinner from now on. Just to save my shoulder when stirring. :-)
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Re: Mash thickness and volume

Post by NormandieStill »

So I stripped the second batch yesterday and pulled off 6L at around 20%. Interestingly this suggests that my second batch was higher efficiency although there are many factors that could come into play here beyond the mash thickness. Looking at my notes I added the malts a little late the first time so it's not surprising that there was a slight loss of efficiency.

Flavour wise there's no real difference in intensity between the two batches. The lacto infection that had clearly taken the first batch has resulted in a very different flavour, but it's no more or less intense. Grain squeezing is not really any easier although I think that for the same mash efficiency I could expect to recover slightly more alcohol from the thinner mash simple due to dilution (The difference between a no-sparge mash and the first runnings of a sparged mash in brewing terms).

I'll mash in my 3rd and final batch this week (time permitting), and I'm leaning towards the thinner mash. Perhaps a compromise between the two. It's been an interesting experiment but I'd need a much more consistent mashing technique to draw any solid conclusions.
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Re: Mash thickness and volume

Post by Ben »

Locking up a consistant mashing technique is really tough! Thanks for posting your results.
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