Explain it to me simply please

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hugh walker

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Denman NSW
Hi there
I am a new brewer in the Upper Hunter NSW. I have just bough some gear to BIAB and to tell you the truth im green and keen on the subject. I have done malt extract before and wanted to make the step up and had a few general queries i thought some old hands could give to me simply and i can expand from there

1. My setup is a 95l nano boiler using lpg gas, biab
2. Can some explain efficency to me and how its calculated. I am understand its how much sugar you get out of the grain prior to the final boil?
3. I see in brewerfriend you add the details of grain to recipe and asks the efficency, is this based off previous results or recipes. it would change each time?
4. once you have done your mash how do you check that efficency to see if its 60-70-80%. Should you have a estimated OG at that point? if its lower your efficency is less than expected.
5. If your efficency and sugar levels are lower than expected what do people to raise them typically?
6. does mashout increase your efficency, is it typical to do that?

Sorry for the questions i just wanted to understand that area a little better. I am keen on experimenting with flavours and keen to do a couple of interesting pacific ales.

anyone around the Upper Hunter area let me know

Cheers and Thanks


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Efficiency is a measure of how much sugar you get from your grain.

Start at around 70% in beer friend and expect to not hit your gravity for the few first brews until you get used to it

I don't know how to check in brewers friend for gravity/efficiency, but in beer smith you put the details of gravity and litres/ wort and it gives you a reading. Might be something similar in bf

You can boil longer (less wort though, more bitterness), add sugar/malt extract to get more abv and increase efficiency. Or do nothing. Personally, i do nothing.

No need for mashout.

Summary: relax with efficiency. Make a beer and see how it goes. Use more/less grain next time if you need to


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To add to what OMC says, once you get your efficiency sussed (over several brews) when it comes to putting together a grain bill of your own, if you want to go for a particular %ABV in your beer, you'll know how how much grain vs water you will need to achieve that % & quantity of product.

Of course, many will just follow a given recipe, and dependant on efficiency you'll either match (or not) the %ABV in the result.


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Efficiency to put it simply is
How much extract you get / What's there to get X 100 puts it in percentage.
Every malt is put through a test (Congress Mash) that measures its potential, what efficiency tells you is how good you are at getting the extract out compared to the test.
Its pretty useful information. When you buy malt commercially it comes with a COA (Certificate of Analysis) that will tell you what is there to be got. It is often expressed in less than obvious forms like Find Grind Dry which pretends there isn't any moisture (that doesn't add to extract), it will also tell you the moisture content, so a malt like a good Pilsner malt might say it has a FGD of 82%, 4.5% Moisture and a Coarse / Fine difference of 1% (C/F a different test that uses a more brewery like grind on the malt) so your 82% would be 82-4.5-1=76.5%
Means that if you did everything as well as the lab, from 1kg of malt you would get 765g of extract.
If at the end of the day you did your numbers and worked out that you only got 685g of extract from each kg of malt.
Your efficiency would be 685/765*100=89.5% (which would be pretty good)

To use the concept, say at the start of the boil you wanted 26L of wort with a gravity of 1.040.
We need to introduce the concept of Plato (oP) its another way to measure wort gravity. oP is the density of a W/W (Weight/Weight) sugar/water solution, if I dissolved 100g of sugar into 900g of water I would have 1kg of a 10% (or 10oP) sugar solution, if you measured the gravity with an hydrometer the SG would be 1.040, to convert between the two the approximate equation is SG=(4*oP)/1000+1, i.e. for 10oP, (4*10)/1000+1=1.040

Back to our 26L of 10oP wort, say you're on second brew and you got 78% efficiency last brew (really the only way to know) with malt that has a potential of 76.5%. The question is "how much malt do you need"
Would you believe there's an equation (learn you to ask technical questions)
Grain Mass = Vol of cool wort*SG*oP / Malt potential*Brewhouse Efficiency.

The volume of cool wort that is 26L at 20oC when heated to about 80oC will be about 3% more so lets say we actually need about 26.8L, time to plug the numbers into the equation. Remember that percent is x/100 so 78% is 78/100 or 0.78.

Grain Mass = 26.8*1.040*0.10 / 0.765*0.78 = 2.7872/0.5967 = 4.671kg

Believe me that's the simple explanation, its also why many (most) brewers use a calculator, but that the basics of where the numbers come from.
Have attached an old COA and a copy of how to do a congress mash, just for fun, if you use more than one malt, you will need to find the numbers for each, do up a weighted average and work out the potential of the mixture and plug that into the equation.

Sorry attached the wrong file, here is the congress mash


    71.5 KB · Views: 63
  • WM272MEL_Pilsner.pdf
    27.8 KB · Views: 30
  • Congress Mash.PDF
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