I thought the serious thesis-like title was appropriate for my little experiment that I started two nights ago and completed yesterday. Of course, there's still sorbet in the freezer for follow-up analysis. :-)
I took a number of photos for the heck of it, so linked to my album below. The photos provide alot of visual data, so I'll try to keep my words here as brief as possible for me.
This study was triggered by "munster" who posted on her experiences making ice cream at home: [BROKEN LINK REMOVED]
Munster generally concluded that increased churning time (total of 50 min. in her machine) improved texture (ie, more creamy and less icy) and didn't contribute to excessive overrun (ie, expansion). I was intrigued by this b/c I've been steadily *decreasing* my churning time (to as low as 5-10 min. for rich custard bases) to limit overrun and achieve a gelato-like dense texture and intense flavor.
While I still need to test this methodology using a cooked custard base, I started w/ peach sorbet. My base consisted of 4 c. of peach puree, 9 TB sugar, pinch salt, 2 TB white wine. I churned the base til what's normal for me for sorbet, about 15 min., basically til it comes together and looks consistently creamy. I then removed half of the base (about 2 cups) and stored in freezer.
I then let my machine continue for about 45 min. with the other half. Munster mentioned that her machine's dasher will get stuck and then reverse when her ice cream is "done." All machines are different though. My dasher is narrow (not a paddle like the Donvier) and stays in one place while the canister rotates. The base gently glides over the thin angled blades, and I don't think it's possible for the dasher to get stuck and then reverse. I got this machine yrs. ago and have no idea where the manual is.
When I returned after 45 min., I was really surprised! The once vibrant-colored mixture was now very pale and *fluffy*. It looked more like sherbet. I didn't have the patience to exactly measure amount of overrun like a good little scientist, but my visual assessment would say that it expanded anywhere from 30-50%. I tasted at 3 time intervals: right after coming out of the machine; after 2 hrs. in freezer; next day after the usual thawing.
Sorbet A (15 min. churning): It tasted very good at all 3 intervals, probably the best after 2 hrs. in freezer. The color was vibrant, texture was suave and creamy, flavor was pure peachiness the instant a small bite made contact w/ my tongue, very little overrun. Good scoopability and slow melting. Next day was a little icy on top and had more of a pleasant "chew", but I had to refrain from eating the entire container.
Sorbet B (45 min. churning): It never tasted that good to me since it was so light and aerated. I could take a big bite, but it would take a moment for the peach flavor to come together and register on my palate. Texture was sort of like those fluffy ICEEs which I've grown out of. It probably tasted best right from the machine, but wasn't very exciting the next day. Scoopability was poor, as it broke apart very easily and slid around when I tried to compress it into a ball. Also melted very quickly. The most damning evidence is that most of it sits untouched in my freezer.
Conclusion: As far as sorbet is concerned, I will continue churning for about 15 min. and not much longer. My machine seems to produce a fair amount of overrun over time. Machines really vary though, so take this into consideration. My peaches were quite sweet so I didn't add as much sugar, which I think made it more icy. I think the yogurt I added in my last strawberry batch also improved texture. More research needs to be done using a cooked custard base; however, I hypothesize that I'll get similar results. Hope you enjoyed my study, and look forward to hearing your thoughts and feedback.