I can't believe I haven't put
this link into this thread as yet

.
I love a simple brewday and know it can be done perfectly with very few measurements and equipment.
Unfortunately I also love testing out things. For example, I'd like to put a percentage on what difference to efficiency leaving the bag until mash out temp does compared to pulling it immediately. This should, for all practical purposes simply be a matter of measuring the gravity at the end of the mash and then again after the bag is pulled at mash out as the volume difference will be almost identical, certainly immeasurable.
I thought I'd do this measurement again today on two brews but cheated by using my refractometer. Suffice to say, that I won't be using it again tomorrow.
There's only one thing I know from all these years of collecting figures - you can never rely on a single reading from a single instrument (let alone done on a single brew) to know whether a change in your brewing practice actually makes a difference. Even if I'd used my hydrometer today on those two brews, I still wouldn't have learned anything - just gathered two more sets of figures. It's repeated measurements over many brews that tell a story and this is hard to do for a home brewer.
When I hear the phrase, "I hit my numbers every time," I roll my eyes because I
know you'll never hit your numbers every time. (Sometimes we just see what we want to see.)
Oh and I do know one other thing... As long as you are in the ballpark, you get great beer.
Measuring precise numbers on a home brew scale is simply not possible especially with a single instrument. (For example, I have four hydrometers and so have an advantage that I can work on my most 'average' one. I also have 11 thermometers

).
If I didn't have this obsession with looking at whether certain things make a difference, I'd happily brew with no measurements and simply rely on The Calculator. Good recipes and experience are certainly a lot more important than numbers.
A good understanding of numbers will help to ensure you get the good recipes in the ball park however.
PP
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