I think as said time is important, at the moment drinking beer made in November 2015, the problem is remembering what you did, so you taste one which is great, then can't do it again because your notes are not good enough.
I find doing the same kit over and over again, Scottish heavy, I get good and not so good brews even though I did them all the same way, so must be down to temperature, now I set the temperature to the same every time, but was back in November last year only controlling the minimum temperature so maximum could be too high, but my notes only say what the temperature was set to, not what the temperature actually was.
So by this time next year I will have been able to sample beers using dried malt, beer enhancer, twin can, treacle, and others, but until next year will not really know what they will finally taste like.
The move to full temperature control also had some set backs. It seems strange to look back, but when I started around 4 years ago I had no real control and to be frank some were better than today's brews. Also some a lot worse, but only one beer has gone down the drain, an attempt to lager a brew. The main problem with the poor brews was too warm, and time does correct that to some extent. But back to full temperature control, I had used stick on temperature strips and had recorded what temperatures seemed to work. I had noted how to start with 17ðC was enough for it to brew and even at 16ðC it was still OK in early stages, but as the brew progressed it needed to be warmer and in the latter stages it needed 18ðC.
So with my new temperature control tried at 18ðC and found that was too cold, and after 20 days the brew was not ready to bottle. My question was why? After considering what I was doing I realised my error was the original measurements. What I had failed to realise was the stick on strip is measuring some sort of average between ambient and fermentor temperature, so when it said 17ðC at start of fermentation the brew was at 18ðC plus, and at end of fermentation 17ðC was 17ðC. With the sensor under a sponge to insulate it from ambient I was measuring much closer to the true temperature.
As a result I found the set temperature had to be 19ðC not 18ðC and that 1ðC made a huge difference, that also seemed odd, but then I realised now I was holding at 19ðC 24/7 but in the kitchen it would drop over night then raise again as the central heating started, this again was meaning all my old data was redundant. But my attempt to brew for 20 days at 19ðC (+/- 0.5ðC) also failed, and I found I needed to split brewing into two stages, first 10 days at 19ðC then second 10 days at 21ðC at this the brew was always ready after the 20 days. But it did not end there, being short of stock I was trying to drink early, and I could taste a green beer, and after 10 days in bottle it was still green, it was then I realised once bottled I needed to either keep bottles warm, or store for a long time, so started packing the fridge compartment with the brew just bottled so the process became.
8 ~ 10 days in freezer at 19ðC +/- 0.5ðC,
1 day in fridge to settle, then transfer to clean fermentor,
8 ~ 10 days in fridge at 21ðC or higher, (no cooling goes to fridge).
8 ~ 10 days in bottles packed around the next brew while waiting for label.
1 ~ 9 months in shed where the snails seem to want to eat off all my labels.
At last I am starting to get a consistent brew. But like many before me I am itching to try new things, so there is that temptation to try more than one thing at a time, my all treacle stout was on reflection an error should have tried just a little first, but I have learnt what too much treacle tastes like now, so can recognise when too much treacle is used now. The same applies to too much sugar, and too much of anything else. To describe what too much sugar tastes like is hard, but too much sugar does do similar to too hot, so until full temperature control I have likely made errors in my notes as to limits of sugar used. Not really tried the brew enhancer, and spray dried malt yet. Made but not tasted.
I do not make just beer, and when making cider or high alcohol mainly liquors, the fridge or freezer is not available to make beer, so on average around 12 brews a year, this means learning what does what is slow. As said most of the first years home brewing notes are useless as no temperature control, but some things have still been learnt, and one major one is brewing takes time. The other and I keep forgetting this one, is the hydrometer shows where you have made errors, it is tempting after doing 12 brews all which take 20 days before bottling to just bottle after 20 days, but some times it takes longer.
My best brew was likely my first brew, my wife started it in the January, it sat in the kitchen until march, when I asked should you be doing something with this, so I took over and bottled, likely it was 60 days on the yeast, then priming sugar added to each bottle, used old green fortified wine bottles, had a real problem filling as 2/3 full and loads of froth, did not know then that syphon tube should go to bottom of bottle. The caps were not a good seal so many of the bottles when opened had rather a flat brew. I seem to remember I left for quite a time before trying, it was not my thing then.
Well I have to admit with all the errors, it was still likely the best brew I have done, or half done, not a clue what kit it was, can was gone well before I took over. But April that year I started to home brew, each brew got worse and worse, at that time I had not got a clue why, now I realise I was leaving them less and less time, and it was getting hotter and hotter, as Winter came in so the brews improved again, and until this year I gave up brewing in the summer.
I got a second fermentor, I got stick on temperature strips, I used electrical stuffing glands to get a really good seal so I could judge fermentor activity, I would count how many bubbles per minute. I put body warmers around the fermentor with air lock sticking out of the top. I thought by that time that I knew it all. Then our fridge/freezer was condemned and we had an insurance pay out on it so bought new, but it still worked so it went to garage. And I started to learn all over again. At first only controlled heat, did not use the cooling, I bought the wrong controller, then finally got new controller and started using cooling as well. At which point started to learn all over again.
I hope you can learn from my errors, however likely you will not, I was really silly in early days, I thought I knew it all, only as I have progressed have I realised how little I know, and not touched all grain.