If you pull espresso from two batches both ground to the same color (Agtron 65), but one was ended at 207°C with 18% DTR and the other at 204°C with 24% DTR, which tends to yield thicker crema in your bar, and why? I’m seeing more stable foam from the 24% DTR on our 12 kg Probat after a 196°C charge and a reduced drum speed, and I’m curious if that aligns with your results.
Same here — ‘24% DTR’ at a slightly lower drop yields thicker, longer-lasting crema for us, likely from extra melanoidins/surface-actives and less cell rupture so CO2 hangs around. Try keeping 204°C but add 10–15 s post-crack and rest 48 h longer; push much further and I start losing aromatics; are you seeing the same when you keep drum speed reduced?
On our Linea PB, the 24% DTR batch gives thicker crema if we rest it 7–10 days and use a gentle 1–2 bar, about 6 s preinfusion — otherwise the foam pops like a shaken soda… The 207°C/18% wins for crema if we’re pulling inside 72 hours, so timing matters more than I expected. @fred_smith1978, have you tried delaying service and tweaking preinfusion to see if the “24%” holds up better?
But we get thicker crema from the 204°C, longer development at Agtron 65 too, but only when brew water alkalinity stays under about 40 ppm as HCO3–; higher buffer knocks it down even with plenty of CO2. Since you’re charging at “196°C,” try pulling the same batch with low-alk water like the BH recipe (https://baristahustle.com/blog/espresso-water/) and see if it still holds. Dropping our water from about 80 to about 30 ppm turned the long-dev shots from big-bubbly to tight foam at 1:2 in about 28 s.
With your 196°C charge and “reduced drum speed,” the 204°C + longer development gives me a richer, longer‑lasting cap because cell walls stay intact and CO2 sticks; the 207°C/shorter dev vents faster. One tweak: hit high airflow the last 60–90 s to strip smoke/oils, then rest 6–8 days. @karenh1989, have you tried adding headspace (8–10 mm) to cut shear?
And lower end temp with a longer finish gives me thicker, more stable crema — if I blast‑cool to under 40°C in 3–4 minutes and serve at day 5–6; otherwise , it thins fast. I think your ‘196°C charge’ preserved core CO2 and kept pores intact, so more oils can emulsify. How fast are you cooling that 12 kg Probat?
I get thicker, longer‑lasting crema from the cooler endpoint + longer dev, but the biggest bump came from a gentle about 2 bar preinfusion for 8–10 s — it slows the initial CO2 dump so the foam stacks instead of blowing out (solid explainer: https://www.baristahustle.com/blog/what-is-crema/). If you stick with the hotter/shorter batch, dropping brew temp 1–2°C can help the cap hold a bit longer; have you tried a soft preinfuse yet?
For me, the 204°C with about 24% dev throws a fatter, more persistent crema because fewer surface oils bloom and the CO2/melanoidin matrix holds instead of popping like bubble‑wrap. The biggest practical win was nudging airflow about 15% in the last minute and cooling under 45°C in about 3 min; on softer lots the 207°C run can puff up more but collapses quicker. If you want the why behind lipids and surfactants, this is a solid read: https://pubs.acs.org/doi/10.1021/jf901183m.
I see thicker crema with the longer development, but the biggest bump came from switching to a 20 g ridgeless basket and keeping about 1–2 mm ‘headspace’ — the screen stopped tapping the puck and the foam stopped popping… Do you get a screen imprint on your pucks with that profile? If I see any imprint, I drop the dose a half gram and the crema stabilizes.