Dialing in the AeroPress (2)

Since my last AeroPress brews I've been having a think about how else I can tweak the brew parameters to reach my target extraction.  I've tightened the grind, I've tried different press speeds, I've allowed the steep time to encroach upon 1min 30 secs, which I think is more than reasonable for this brew method and I wouldn't want it to take any longer. So two questions remain:

1. Why isn't the TDS higher?
2. How else can I increase it? 

Why isn't the TDS higher
I need to continue thinking about this more, but I think I'm not getting a good enough diffusion process to pull out the solids from the grinds. Possible reasons (ignoring the parameters already mentioned) include:

• Water temperature too low... I doubt it. I'm being very careful here (remember the übercosy?)  although there's a balance to be found between the longer steep time and temperature loss.
• Dose too low.
• Problems with the grind ... perhaps particle distribution rather than size setting. The Ggggia MDF isn't a bad domestic grinder at all... underrated in my opinion... but perhaps there are issues that I hadn't considered.

I shall continue to muse, but in the meantime I'm going to increase the dose as it is the easiest one to vary.  It may reduce some of the sourness I'm getting too... which I'm sure isn't coming from low brew temperature.

I typically work to a 1:16 ratio but I'm going to go richer, first trying 1:15 and seeing how it goes.

(As an aside, at this point in time I prefer working to brewing ratios in the format of 1:15 - i.e. weighing the grinds AND the water - rather than, say, 60g/litre. My preference stems from my espresso approach to brew methods... there is now (finally and thankfully) a trend towards using weight to measure and control espresso shots. For example, Square Mile have the following sugggested brew parameters for an espresso on their website:

18g in  ... 27-29g out.
Using a consistent unit of measure just seems more appropriate to achieving consistency.)

Brew (I've decided to stop numbering them!)

To be updated later today...
Nope... had to take Lulu the cat to the vets. Updated another day :)