Hi there johns
. I had a go at answering this question a few days ago but the only thing I achieved was getting drunk and having a psychotic episode
. The title, 'Chasing numbers,' brought on some PTSD of the days when a few of us spent months making sense of the numbers given in various brewing software.
Let me have another go and let's see if I can save you a bit of the frustration we went through.
Two other quick things first...
1. There is no correct roller gap for a mill. It depends on its roller design, width and even on how it is powered. Check this post
2. Your numbers will not go higher by holding some water back and using it as a sparge so continue to full-volume mash if you can, for 90 mins, and if possible do a mash-out.
Chasing your numbers
There are many good issues you have raised in your post and the answers are simple but will require some study and reading. When chasing numbers there are several areas of concern.Brewer Error
Please read Some Common Reasons for a Low Efficiency Reading
There are two points I'd like to highlight more from that link. The first is that you can't tell from single brew if you even have an efficiency problem. Just bear that in mind as you might be worrying about nothing at this stage. (I'm working on the theory that this is your first all-grain brew)
Secondly, the terminology used in the home brewing software world is very poor. It is especially poor when it comes to the term, 'efficiency'. BIABrewer.info has put a lot of work into creating easy to use, clear terminology. For the moment, you will need to study this post on Brewing Terminology
. There are six main terms to learn which are highlighted at the bottom of that post.Software Error and 'Friction'
thughes has rightly suggested that you use The BIABacus. In the same vein that BIABrewer.info has spent time on giving us clear, non-clumsy, unambiguous terminology, they have also done the same for software. It was not their original intention and, in fact, months and months were spent here trying to make other software easy to use. thughes advice to use The BIABAcus is correct for many reasons as here is what was found when examining other software...
There were one or more major errors in nearly all the software that was checked. This process took many months as we naturally assumed that all software would be correct. Just be aware of that.
The poor terminology used in existing software means that it can take a long time to check a single recipe as two users can use the same program in two completely different ways.
The design of existing programs is very inflexible and educates people into myths. A good example you'll often see on other forums is the statement, "I get 80% efficiency on all my brews bang on every time." There's 3 problems with such a statement. Firstly, who knows which efficiency they are talking about? Secondly, it is impossible for a home brewer to get the right numbers every time unless you do a bit of mental juggling as we just don't have that level of accuracy. Thirdly, unless they are brewing the same gravity brew every time with exactly the same spec grain, then they should not
be getting the same "efficiency" on every brew.
Another major problem was that it was very easy to push a single wrong button in some other programs and come up with totally incorrect answers or destroy the integrity of the recipe. The design is unsafe.
Explaining how to set up and then use other software safely and explain the number, terminology and design errors mentioned above became so time-consuming (and hard for the user) that BIABrewer.info abandoned that avenue and some of the guys here started working on improving The Calculator. You now have The BIABAcus.
Even though it is free and not in program form, it is important to realise that it is revolutionary. It is a 'low-friction' (user-orientated), safe, fast to learn, powerful, flexible, highly educational tool with many features no other brewing software has.What we can do now
Once you have had a bit of a read of some of the links above etc, I think post the .bsm file of your recipe up here. I will take a look at it and we can work from there.