AG #2 - Help working out my efficiency (please)

[salnajjar]

So, I thought I would counteract the lack of end product on my first AG attempt so I did a massive increase on my water amounts this time around. I'm now trying to work out my efficiency as it seems quite low still.

Grain bill was:
4.96Kg Marris Otter Pale
1.48Kg Flaked Barley
0.43Kg Roasted Barley

I put 13 litres of water into the mashing.
I sparged with 19 litres of water.

Total into the boiler was only about 16 litres.
Total into the fermenter was about 13 litres.

My BG was 1036.972
My OG was 1055.784

I'm working out my efficiency as being in to 63% range, but I'm curious if I'm calculating something wrong. What does anyone else calculate my efficiency as?

Thanks

Seri

[simple one]

Yeah I get that as about 63% eff. Thats pretty low.... Is it deliberate?

[salnajjar]

I wish, I was shooting for an OG of close to 1.070 for a nice strong stout... very odd as my mash temp seemed quite good and my sparging went a lot better on this attempt than my first brew...

[simple one]

The only two things I could sugest are sparging more.... or do you treat your water?

[salnajjar]

KH test of water, punch end figures into Grahams Water Calc. Put a campden tablet, CRS and whatever salts are recommended into the water for both the mash and the sparge (adjusting for volumes).

I'm wondering if mashing with more water would be better?

The pan I use to heat the water only holds 20 litres for I'm limited to around 40 litres total for mash & sparge...

[adm]

Firstly, your water calculations are way off - so bear with me as I'm a bit drunk....

Right....here's some of my rule of thumb stuff again - your mileage may vary.

Firstly, you've got about 7Kg of malt in there. You need to decide what malt/liquor ratio you want in your grist. 2.5L per kilo comes recommended by many, so from that basis, you need at least 7 *2.5 = 17.5 litres of water to kick off with for your mash. You only used 13 and you don;t seem to be topping it up before sparging.

Next... you need to calculate how much wort you want to go into your boiler. Using my personal numbers, I would want at least 31L in the boiler for a 90 minute boil (assume 10% per hour boil loss - or about 5L lost to evaporation over 90 minutes) This would mean you'd get 31-5 = 25 litres out. Minus wort lost to deadspace in the boiler and hop absorption - assume 2L for these for now and you should end up with 23L (or 5 Gallons) into your FV. Now of course, if your boiler retains more liquid, or you use more hops (assume 15ml per g of hops for hop absorption) you need to make sure you have more water into it - so just adjust as neccessary.

Now you have two of the three key pieces of information you need:

1) How much water you need for the mash
2) How much wort you need to go into the boiler

But you also need to know how much liquor will be lost in the mash. Luckily, this is pretty simple - you can assume 1L per kilo of grain being absorbed by the grain. Then add any dead space that your mash tun has. Let's call that 1L for now - yours may be different and you need to measure it to be sure.

So. To calculate the total amount of water you need ( and assuming batch sparging), you take the total amount of wort you want into the boiler - in this case 31L and divide it by the number of batches in your sparge. Let's assume 2. You basically want equal amounts of wort from each batch just to keep things simple.

So - 31L/2 = 16.5L

So you need to collect 16.5L from each batch.

For your 7Kg grist, you've used 17.5L to mash with, but you will also loose 7L to grain absorption, plus 1L to mash tun deadspace - so expect to only get 17.5-8L = 9.5L of wort out UNLESS YOU TOP UP with extra water.

So add another 8L to your mash tun after the mash is finished but before you run any wort off, then stir it around. Now you've made up your losses in advance, so you should be able to run off 16.5 litres from the first batch.

Now for the next batch - as you've already taken care of the losses and the grain is saturated and the deadspace is full, you just need to add the rest of the water (16.5L) to the tun, give it a good stir around and run it off - you should collect exactly what you put in - 16.5L

So the water calculation looks like this:

Assumptions:
7Kg Grist
2.5L/Kg mash
1L tun deadspace

Mash in with 17.5L
Top up with 8L
(Collect 16.5L)

Second batch sparge, add 16.5L
(Collect 16.5L)

Total - 31L into Boiler
Total water needed 42L

You've only used 32L total so there's no way you've got all the sugar out of the grains. BUT - even so, you should still have a much higher pre boil gravity than you have, so I can only assume your mash is too thick and you aren't getting a proper conversion of all the starch to sugar.

For the efficiency - use approx 300 sugar points per kilo of grain as a baseline at 100% efficiency. Times 7Kg of grain gives 2100 points.

Divide that by the number of litres. You got 16 litres into the boiler, so at 100% efficiency you should expect 1.131

With a reading of 1.037, it looks to me like you only ended up with around 37/131 = .28 - or about 28% efficiency - which means you left most of the sugar in the mash tun due to not using enough water to convert the starches, or wash the sugars into the boiler.

(Disclaimer - my maths may be fcuked as I'm drinking 11% Trippel)

Anyway...long post, BUT - I think you need to do the following on your next brew.....

1) Get the amounts of water right
2) Make sure the mash temperature is correct (try 66C for 90 mins)

If you can get those dialed in, you'll be ahead of the game.

Why not post your next brew plan so we can all run the numbers before you go for it?

I hope this all make sense...I'm off to my bed now!

[salnajjar]

Wow, okay, I'm going to have to come back and re-read this post tomorrow when I'm sober myself. At first read it looks to have all the information and then a ton more that I need.

I plan on doing another brew tomorrow (if my starter is acceptable) so I will post my plan on here before hand for input and suggestions...

Thanks for this though, it's really helpful.

[Totem]

Sticky that post!

[salnajjar]

I'll second that! Perhaps change the title to something more helpful to people stumbling on it however...

[trucker5774]

Nice one ADM. Good post, I felt like I was doing a brew! It is very simply when you are actually doing it (not saying the explanation wasn't.........or that ADM IS )
the following link may also help http://www.hopandgrain.com/batchspargecalc.aspx

[Scooby]

Adm has explained it all really well A couple of points to note, have you calibrated your vessels? It's a good idea to weigh out 1 or 2kgs of water (1-2l) and add to the vessel, then mark off, add again and mark etc

Total into the boiler was only about 16 litres.
Total into the fermenter was about 13 litres.

My BG was 1036.972
My OG was 1055.784

This is way out and doesn't stack up, from my working 16l at 1.037 boiled for 90 min with an evaporation rate of 12%/hr would leave you with 13.12l at 1.045

You need to calibrate your vessels, follow Adm's workings as accurately as pos and I'm sure you'll get good results.

[salnajjar]

Quick Q's:
Does the top up water want to be around 67c? Or, should I be taking a temp reading of the mash tun after mashing and try and bring the temp back to around 67c, or, something completely different?

Also, when I add the top up water, do I want to give it a good old stir? I guess so, but doesn't hurt to ask.

Thanks all again, so much help and it's all really appreciated.

Seri

[Scooby]

I add water at 80c that way the mash is raised to approx 72c which helps to dissolve the sugars and yes stir then let stand for 10mins, circulate a few jugs then drain.

[salnajjar]

By jove I think I've got it!

So, I've just put my third AG on to boil (I know I said I would post my method here, but I wanted to see if I could work it out myself first).

There's a ton more liquid gone into the boiler than my first 2 attempts and the overall BG is still pretty high for the volume (1040).

Total grain bill was 4.95Kg, 4.5Kg Marris Otter with 0.45Kg of 120EBC Crystal.

Will be interested to see what the OG is and if I get the full 21 litres this time... I know I still need to get my efficiency up, I think insulating my mash tun some more and perhaps leaving to stand for longer once I top up the water in the mash tun will help...

[salnajjar]

I've just worked out that my efficiency on this current brew is 73%.

I want to say a massive thanks to you fine beer loving folks on this forum, I've gone from knowing absolutely zero about brewing beer to now having 3 AG brews on the go. The next step now is in how they taste and getting to know the finer points of brewing.

But, thanks once again, and a special thanks to adm for his long and very helpful post.

Seri