Very low efficiency mash-help!

[Alun]

I'm new to all grain brewing. I can't get hold of decent equipment, so I've tried a few "pilot scale" all grain brews. These went well, but I was doing my mash in a the same 10L pot that I do my boil in.

So I got hold of a coolbox and put a tap in it, and used that for a mash tun. I can't get hold of a big boiler here, so I got hold of two 10L pots for the boil. I figure go for a high gravity wort, then top up with water to the desired OG before pitching the yeast, looking for a final volume of 20-25 L. Mash 5 KG grain in 12.5 L water (strike temp 72) for 90 mins (final temp was 62). Then batch sparge 2 x 9 L, allowing me to boil each nine liter batch separately. I recon I could then combine the two batches and should have a high gravity and a volume of about 15L. Like this:

3Kg Pale Ale Malt
2Kg Pils Malt
50g Crystal Malt

Using Jim's recipe formulation this should produce something like

5 x 300 / 15 = 100

for a "perfect" mash, but still somewhere in the range of 1070-1080. Or so I thought. When my boil was finished and I'd cooled it, I had a volume of 15L, but this is too little for my Hydrometer to stand in (it hits the bottom of my vessel). So I added a couple more liters of water. Now my volume was 17.5 liters. The gravity was only 1042. I couldn't believe it. Modifying the above to allow for a volume of 17.5 liters, my gravity should still have been 5 x 300 / 17.5 = 85, and with an efficiency of only 0.7 I should still get a gravity of something like 1060.

My sparge run off never ran clear, and I have read here that this can mean starch in the wort? I'm really flumoxed. My mash was for 90 mins, and the final temp was 62, initial temp 65 according to the strike temp calculator. So why wouldn't the enzymes work? I bought the Pale Ale malt last summer, but it was whole grain and I crushed it myself the day before the mash. The Pils malt was bought just two weeks ago.

Is there a mixing problem? Should I have stirred it? I was worried that that would cause a big temperature drop.

Any help would be appreciated. Thanks.

[Alun]

I batch sparged 2 x 9 liters. I had to do this because I have two pots for boiling of 10 liters each. I have to boil both batches separately because no one sells big boilers here in Finland.

I was not concerned about water pH, water's really good quality here in Finland, when I've measured pH before it's always been fine. This time I didn't do it, maybe I should have. Do different malts produce different pH in the mash? I ask because I have not used Pils malt before, only Pale Ale malt, and I haven't had a problem before.

[yojimbo]

Hello were you having any problems before you changed your set up ? as this is your first run with a cool box may be you just need to have a couple more mashes to see if its just how your going about mashing and sprging, or may be look at how the garain was crushed it could have been undercrushed posibly.

Like chris said a bit more detailed info would be good especially on how things were going before to make a comparison.

[Alun]

Hey, thanks for the help. I was worried about my mash being the problem. Now I think it was probably the sparge. I should have used much more sparge water, twice as much actually.

In the past I've done small scale mashing in a 10L pot that I do my boil in. With 1.2 Kg of grain and 3 L of mash water. Lautering using two 10L buckets, one inside the other, the top one with small holes cut in the bottom, and the bottom one with a tap. I've been batch sparging this with 2 X 4.5 liters and boiling about 9 liters. I have been getting about 7L of beer. It was simple to maintain the mash temperature by keeping an eye on the pot and putting heat into it if it dropped below 64. I kept it between 64 and 68. My beer came out OK. But I was sparging about 1.2 L of grain with nine liters of water. This time I think the mash was OK, 65 to 62 is within the range for beta amylase (is that right?). But I sparged 5 L of grain with only 18 L of water. A 7.5 to 1 ratio originally, became a 3.6 to 1 ratio this time. That's less than half the amount of sparge water. I think that probably explains the vast majority of the problem.

I'm going to use much less grain next time, maybe 2.7 Kg, and sparge off 2 x 11 liters. That should give me more of the sugars. It'll also give me more space in my mash tun.

What do you think?

[Alun]

Ah, I'll go for 18 L brew length.

[the_great_okapi]

Maybe I've missed something, but haven't you just said that the two batch sparges were combined (~18 L) and then boiled (to 15L) - what happened to the original run off, the high gravity one from the initial 12ish litres (minus grain retention)?

You need that to calculate your efficiency. You seem to have just done the batch sparges, unless I got lost somewhere.

[Alun]

Hi the great okapi (brilliant name BTW).

Maybe I've missed something, but haven't you just said that the two batch sparges were combined (~18 L) and then boiled (to 15L) - what happened to the original run off, the high gravity one from the initial 12ish litres (minus grain retention)?

So you'll have to excuse me if I have used some of the terms incorrectly. But my first batch included the water from the mash like this:

Wort required 18L (2 x 9L)
Total H2O in Batch #1 = 14L
Total H2O in Mash = 12.5
Top up mash with 1.5 L sparge water.
Run off as Batch #1
Add 9 L H2O for Batch #2

So my batch #1 included mash and sparge water, and my batch #2 included only sparge water. Is this wrong? I got these figures from the the batch sparge calculator in the hints and tips section on this very site.

[Alun]

Hi Chris-x1, I've been going through my notebook with details about my trial runs that went OK, and I think I have found another reason why my efficiency was so poor. It may be due to the pH of the mash. Because I'm a molecular biologist I feel comfortable scaling things right down, so some of the amounts here might seem very small to you.
In my first attempt to make an all grain beer I wanted to produce 4.5 L (so I could ferment in a wine demijon), so my recipe was:
560g Pale Malt
50g Crystal Malt
0.61 Kg grain bill.
But I mashed in 2 L of H2O. That means that my H2O to grain ration was 3.3:1. It was this mash that I measured the pH from.
Then I batch sparged with 4 L of H2O, giving me a total volume of 6 L for my boil. Being such a small volume I lost a lot of this during the boil. My final volume after the boil was 2.5 L with an OG of 1052 (much less than I estimated but I topped it up with H2O to an OG of 1040)).
I can calculate my efficiency from these figuers:

0.56 x 300 / 2.5 = 67.2
0.05 x 240 /2.5 = 4.8

Total theoretical conversion = 72

Efficiency = 52/72*100 = 72.2%

Given that pH is volume dependent, it could well be that using a smaller ration of H2O to grain mass has changed the pH inside the mash (2.5:1 as opposed to 3.3:1), after all my water source hasn't changed. That coupled with the fact that I sparged with too little water off might well explain my problem. One problem with sparging is that in this scaled down recipe I sparged with 4 L of water, and my mash was 2L. I did this because "Homebrewing for Dummies" says that sparge water should be about twice the volume of the mash water. Looking at some standard homebrew recipies this seems true. For example using 4Kg of grain and 10L mash with a 30L boil volume, it's clear that 20L has been used for sparging. I don't see how I can do that when I include so much water in my mash. On the other hand my mash is more dilute than it is for a 2.5:1 ratio, so getting away with less sparge water might be OK.

So I have a new plan:

3.2Kg Pale Ale Malt
0.3Kg Crystal Malt

at 3.3 Liters mash water per Kg of grain, I mash with 11.5L water. (That's almost as much water as I used for the 5Kg grain bill mash, which was 12.5L). According to the recipe formulation tool at hopandgrain.com, with a 70% efficiency I should get an OG of 1041 for this grain bill for a brew length of 18L.
Then I'll sparge with 2 x 11.8L (assuming 15% loss from the boil in the batch sparge calculator on this site)

For boil 23.5 L
Batch #1 = 15.5 L
Mash vol = 11.5L
Top up with 4L
Batch 2 = 11.8L

My only problem then is that I have to boil my wort in three pots. How about hopping for this sort of thing. I thought it would be OK to hop just one of the pots, it's analogous to extract brewing then isn't it? Then we hop our concentrated wort and dilute it afterwards.
I know there's a lot to digest there. What do you think?

[the_great_okapi]

Alun, I clearly misunderstood your first post, sorry - I thought you had not collected the first runnings or left a lot of water in the mash at the end (9+9+x with x from the mash).

In addition to what Chris said, before I switched to full boil I had a nightmare getting the desired amount of bitterness in my beers too, even adding to the more dilute pot - I think that adding all the hops into a small kettle seriously reduced utilisation beyond the amount I expected using the Tinseth method - I think the Garetz method was probably closer to the mark. Whatever, you still need more hops if they aren't being jostled about as much as in a full boil.

[Alun]

OK, thanks, I'd been using "Homebrewing for Dummies" a bit, but it's a pain because it uses American gallons and uses lb and oz, and they mean nothing to me. What you wrote is similar to what I suggested I think. The difference being that I'll mash with 3.3 L of water per Kg of grain. So my mash will have ~11.5 L of water. I'll lose about 3.5 L of this to the grain, and about 0.2 L to the dead space. So I'll add 3.7 liters of sparge water for my first batch, and 11.5 Liters for my second.

[Alun]

Hi Great Okapi. I haven't had any problems with hopping so far. Until recently I was doing only extract brewing. I'd do my boil in a 10 L pot and then simply dilute with water to my desired volume. I don't think I had any problems doing this. Generally I'm aiming for a sweetish beer with a hoppy aroma, so I tend do add the bulk of my hops towards the end of the boil anyway.

[sheffstevie]

Hi - first night on the forum and hello to all - I noticed this post after watching a bloke on a you-tube video stir several kilos of grain into a mash tun in about 10 secs and achieve a settle out temp of 66 degrees from a quick dip of the thermometer in just one area and depth of the mash tun - now, notwithstanding the constraints of time within a video edit, the crucial thing over looked here is that if the grain is not fully stirred in to the hot liquor there will inevitably be pockets of dry grain which will result in unconverted starch within the mash. - Result? Cloudiness in the finished product as this is carried over through all the subsequent processes. The original poster of this problem had both low extraction rates and cloudiness problems(" My sparge run off never ran clear") and stated "Is there a mixing problem? Should I have stirred it? I was worried that that would cause a big temperature drop" yet nobody picked up on this and the debate meandered so off topic it got into Stephen Hawking territory at times! - Brewing (whether home or commercial) is still analagous to the cooking process and basic principles apply to both - If you can sweat some onions and garlic without burning them in a nice oil or butter and then add a few herbs , tomatoes and seasonal ingredients and season accordingly you will have a sauce that will rival most average italian restaurants offerings at a fraction of the price - as long as you give it a bit of love and care. If you fry the **** out of the garlic and onions at the initial stage and empart a bitter flavour nothing you do subsequently will get rid of this reek and you may as well sling it down the khazi!

[Parva]

I may be stating bad habits here but it works for me. I use a 28l 'Thermos' mash tun as supplied by H&G so if yours is a different size then it won't apply.

I half-fill it with 82c water (by sight) and add my grain whilst stirring (dad comes in handy for adding the grain whilst I stir). I don't preheat it at all and from experience I've found that I end up at 67c after adding all of the grain and stirring it in. Whilst that mashes for 90 minutes (with a stir at 60 minutes) I make sure that I have the sparge water ready at 82c.

90 minutes pass and I now fill the mash tun (Thermos) to within 1 inch of the brim with 82c water. This brings the contents upto about 74c, stir it in and leave 10 minutes before running the first couple of litres off to a jug and recirculating then run the whole lot into the boiler.

Batch 2, fill the mash tun to about an inch of the brim again, stir, leave to rest, recirculate the first runnings then run off to boiler.

I usually end up with about 32 litres and I boil the hell out of it for 90 minutes and end up around 23 litres after losses to hops etc.

The point is that you don't have to be scientific and end up with exact quantities. Get used to your equipment and get sloppy, brewing beer is an art and a science, you can take either road and still produce fantastic beer but one is less trouble than the other.

[Alun]

Hey Parva and sheffstevie. I think mixing is certainly part of the problem. Good mixing is essential for any enzymatic reaction. Still I'm trying to improve my method empirically, and the only way to do that is to stick with what works and change what doesn't work.

I did some calculations over the last week or so, and it's apparent that my efficiency was only 47% I estimated this by plugging my recipe into http://www.hopandgrain.com/formulator.aspx I think part of this was the volume of water I used in the mash. My small experimental mash had used a greater volume of water per kg of grain, and pH is a measure of hydrogen ion concentration, so less water means more concentrated hydrogen ions, and lower pH. My original pH had been 5.3. On the weekend I tested this hypothesis by adding a greater volume of water to a new mash:

3.0kg Pale Ale Malt
0.35kg Crystal Malt
0.15kg Chocolate Malt

Mash with 3.3L/kg of water (total vol 11.55L). I made a couple of other changes, I pre-warmed my mash tun, and I used a strike temp of 71C because I used more water. This time when I measured my temperature at the end, it was 68C, a bit higher than I expected or wanted. If I lost 2 C then it started at 70, which is a bit high. This is not a problem, I'll slightly reduce my strike temp next time, I want to aim for between 64 and 66. But I got 13.5L of wort at 1043. This is a 60% efficiency by my estimation. Not necessarily brilliant, but certainly much better than previously. As I understand it beta-amylase is more efficient than alpha-amylase, so a mash temp of 64-66 would improve efficiency over a mash temp of 68-69C, but would extract less of the colour and flavour from the grain. Obviously with a greater volume of water per kg of grain there is bound to be better mixing anyway. But I agree, there almost certainly was an issue with mixing in my previous attempt.

On the other hand I put the original beer to it's secondary ferment on the weekend, and it looks OK. Tastes brilliant, it's got a very very bitter taste and a wonderful citrus aroma. It's also clearing better than I thought it would, though it might retain some haziness, only time will tell. Well, with luck I'll get some nice Golden Ale from it.

This is how I figure it on pH, for those interested in my reasoning. If there's mistakes in my calculations then apologies.

5.3 = log (1/[H]) (where [H] = conc of hydrogen ions).
therefore
10^5.3 = 1/[H] (where 10^5.3 = ten to the power of 5.3)
therefore
1/(10^5.3)=[H]
so
1/199526 = [H]
so
[H] = 5.012 micromoles of hydrogen ions per liter (or 0.000005012 M)
because there was 3.3 liters per kg of malt we can turn this into an absolute amount of hydrogen ions
5.012umoles/L x 3.3 L = 16.54 umoles of hydrogen ions.
If this amount remains constant per kg of malt irrespective of volume, then we can work out the concentration of hydrogen ions, and hence the pH of a solution of volume 2.5L
16.54umoles / 2.5L = 6.616 umoles/L
therefore
[H] = 6.616 umoles/L
so
[H] = 1/151152 moles/L
therefore
[H] = 1/10^5.179 moles /L
so
1/[H] = 10^5.179
therefore
log (1/[H]) = 5.179
which is the pH of the same absolute amount of hydrogen ions in 2.5L

So by keeping the quantity of malt the same, but reducing the volume of water, my pH has gone down (theoretically) from 5.3 to 5.179. I reckon it's always worth bearing in mind that we can affect the pH of our mashing system by adjusting the volume of water we add to the mash, rather than just treating the water.

[Alun]

Of course you're right Chris. I didn't mean to imply that one can solve the problem of high pH water simply by changing the volume of water used in the mash. But I also think it's good to bear in mind that water treatment isn't always necessary. I was more interested in why my mash had such a low efficiency, when it had worked previously. I suspect there were several problems with me changing my method (admittedly without putting enough thought into it), and one was changing the volume of water in the mash.

It also strikes me that people have been making beer for thousands of years, and for the vast majority of this time they didn't have the ability to treat their water at all. I'm guessing that people who made beer in historical and prehistoric times must have had many and various different ways to get a fermentable product from their mash, whatever the quality of their water source.

I'd be quite interested to know how they did it. Do you know of any literature that discusses how beer was made historically, and how they got around the technical problems associated with different water types in different locations? My master's degree is in biotechnology, and I'm quite interested in how biotechnology has been used in low tech settings to solve problems. Brewing is one of the oldest biotechnologies in existence and it's a fascinating science.