timcunnell
Regular.
Thanks Covrich. How do you calculate the % then? That bit has me baffled!! When you refer to 65% - what is that 65% of?
Sorry about all these questions! But I must say I am finding all this incredibly helpful!
Question about BIAB and sparging...
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Thanks Covrich. How do you calculate the % then? That bit has me baffled!! When you refer to 65% - what is that 65% of?
Sorry about all these questions! But I must say I am finding all this incredibly helpful!
MyQul
Chairman of the Bored
65% of the potential 100% of the sugars you can get from the grain. I use brewmate to calculate my efficiency but I'm still not sure I'm doing it right as I'm so bad at maths. I prefer to think of it as more a case of did I hit my OG target/brew length target as my brain can cope with that
timcunnell
Regular.
Ah thanks MyQul - that makes sense. So not sure if this is a daft quesiton (probably!) but is the 100% a "known" figure? Presumably an OG derived from the particular grain bill used?
There are a few different measures of efficiency, but most recipes assume around 70% 'brewhouse efficiency' (most brewers with a decent process can get 70% of the achievable sugars from their grains out of the end of the brewday process and into the FV). The 70% is a measure of what can be achieved in a real world brew process for a particular grain bill against some ideal laboratory process to extract maximum sugars.
In practical terms, what matters is:
If you are hitting your expected Starting Gravities when following recipes then your process is good, if not you may want to work on your efficiency with improved mash/sparge processes or different equipment, or just add a bit more pale malt to compensate.
This blog entry on beersmith tries to explain things, my maths is pretty good but trying to get my head around this in any real sense makes my brain ache - the only way to stop the ache is stop thinking about it !
http://beersmith.com/blog/2008/10/26/brewhouse-efficiency-for-all-grain-beer-brewing/
In practical terms, what matters is:
If you are hitting your expected Starting Gravities when following recipes then your process is good, if not you may want to work on your efficiency with improved mash/sparge processes or different equipment, or just add a bit more pale malt to compensate.
This blog entry on beersmith tries to explain things, my maths is pretty good but trying to get my head around this in any real sense makes my brain ache - the only way to stop the ache is stop thinking about it !
http://beersmith.com/blog/2008/10/26/brewhouse-efficiency-for-all-grain-beer-brewing/
MyQul
Chairman of the Bored
yes that's right. Each type of grain or other fermentable is a certain percentage fermentable which is know. Or to think of it another way 1kg of a particular grain will give you a known OG figure. Eg. I'm pretty sure table sugar is 100% fermetable (but I'm sure someone will correct me if I'm wrong)
MyQul
Chairman of the Bored
Don't confuse the poor chap! :lol:
Two or three months ago there was a thread discussing what exactly 'efficiency' means. a forumite found a reference link and there turns out to be about 7 different 'efficiencies' that a brewer can take into account. My head nearly blew up :electric:
Redron
Regular.
I know what you mean, most explanations start out with 'it can be confusing' or 'there are several ways of measuring efficiency at different points in the brewing process'.
Absolutely clear as mud, or just bottled wherry :rofl:
timcunnell
Regular.
Thanks for your replies at input guys - I really do appreciate it!
So to summarise - brewing efficiency refers to how much sugar you extract from the total amount of sugar that is in your grain, right?
So just a further thought (I can't help asking more questions, sorry!!) the recipe I am brewing tomorrow (brown porter) specifies a target SG of 1042. So presumably this figure must be based on the assumption that a particular efficiency is achieved? Is there a "standard" efficiency? I think earlier I read 65%?
I don't really mean to labour this point too much! I haven't got even one AG brew enter my belt yet so really I need to start with that. I am just thinking that by making some really good notes about my brewday method tomorrow I can use the target SG and my actual SG to evaluate whether my technique is adequate or if - for example - I need a better way of sparging, or whatever it may be.
So to summarise - brewing efficiency refers to how much sugar you extract from the total amount of sugar that is in your grain, right?
So just a further thought (I can't help asking more questions, sorry!!) the recipe I am brewing tomorrow (brown porter) specifies a target SG of 1042. So presumably this figure must be based on the assumption that a particular efficiency is achieved? Is there a "standard" efficiency? I think earlier I read 65%?
I don't really mean to labour this point too much! I haven't got even one AG brew enter my belt yet so really I need to start with that. I am just thinking that by making some really good notes about my brewday method tomorrow I can use the target SG and my actual SG to evaluate whether my technique is adequate or if - for example - I need a better way of sparging, or whatever it may be.
If this helps take a 23l brew
5KG of Maris Otter at the standard 70% efficiency will give you an OG of 1048
If you get 65% you will have 1045
But if you end up with something poor like 55% it might be 1038.
The main thing you want is consistency , obvioulsy if you're getting 55% you will want to look at ways to improve that but as long as you are getting around the ball park you want then thats what matters.
If you find you are more 65% everybrew and wanted to make your OG on teh recipe just bung some extra MO in..
Does that help??
Most recipes don't specify an assumed efficiency, but should be achievable with a typical setup by a reasonable brewer.
If you get somewhere close to 1042 on your first all grain brew (1040-1044) then you have done a good job. If you are further away then you probably need to work on something, but you will still get decent, drinkable beer so no great worries.
Get a few brews under your belt and if a pattern develops with your results, for example, you are always low on your starting gravity, or the volume of wort you are achieving in the FV is low then it will be clear where you need to concentrate your efforts to improve your processes/techniques.
Home brewing should be an enjoyable experience so try and enjoy it, the beer you produce should be superb even with a few learning points along the way. Think of it as a learning journey but with great beer along the way as you learn.
timcunnell
Regular.
Thanks Covrich! Yes, that is really helpful! So 70% is the "standard" efficiency that recipes tend to assume, is that right?
And I can see now that 42/70 x 65 = 39 (or 1039) ((well - we'll say 1038 obviously!). But I am guessing that is how its worked out?
Most importantly, I think I now get the point that the main thing is to have a consistent and predictable efficiency (through consistent method) and that way one could always adapt a recipe with more (or even less) fermentables if aiming for a certain SG.
Thanks! :)
And I can see now that 42/70 x 65 = 39 (or 1039) ((well - we'll say 1038 obviously!). But I am guessing that is how its worked out?
Most importantly, I think I now get the point that the main thing is to have a consistent and predictable efficiency (through consistent method) and that way one could always adapt a recipe with more (or even less) fermentables if aiming for a certain SG.
Thanks! :)
MyQul
Chairman of the Bored
It depends where you get the receipe from. Some books, for example, with receipes will state that all the receipes are based on a particular efficiency percent
I take your point MyQul, some do, my post should have been clearer !
I think Graham Wheeler assumes 75% efficiency for his recipes.
My brain is hurting again :lol:
timcunnell
Regular.
Yeah it would mean you were getting more than 70%. By my calculations I think you'd be getting 76% efficiency on the assumption that you achieved 1052, and 1048 = 70%.
MyQul
Chairman of the Bored
:lol:
tbh I always use 72% when I input receipes from anywhere into brewmate as I find this works for me
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