I have tried making panettone on and off for years. A few times I have had modest success--not the huge open crumbs you see on Instagram but still a decent and serviceable result!
This year I'm diving in again but I've had terrible luck. In the past, even with weak LMs, my first dough would always triple overnight. This round, I have continually woken up to a primo impasto which has barely budged. I've tried 4 times with 3 different starters and each time has been a failure. The first two starters were poor performers and I retired them. My newest LM which I created from apple yeast water is a beast, tripling super fast at any temperature. I had such high hopes. Alas, this one too failed to properly rise my primo!
Some other info:
--the LM is young, only 2 weeks old. But in the first few days it was already tripling reliably.
--i usually do one cool feed at 16-18c and one warm feed at 26-28C. 1:1:.43. I'm still figuring out temps and timings because at 18C the starter has often already peaked by 8 hours. I've recently tried higher ratio feeds to extend proofing times.
--I don't know how accurate my pH meter is for solid doughs but I'm consistently getting readings in the range of 4.3-4.5, sometimes higher. I have not been able to get it down to 4.1.
--the scent is usually fruity and lightly acidic
--grandi lievitati always goes well, triple at 28C within 3 hours. But then primo (26-28C) doesn't budge after 12 hours. I bump up the temperature and wait and it will finally triple after 18-20 hours and be very acidic.
--I've been using Giorilli's formula every time
I think this is fine. You're not trying to pull the LM out of maintenance at its peak - in fact, it's typical for the LM to acidify down to 3.8 - 3.95 by the end of maintenance.
This is kind of counterintuitive, but this happens to me when my LM is too acidic / carrying too much acid load. In my experience, going into a primo with a LM that has a pH that high does not end well (I've stubbornly done it many times, even after knowing better).
You're saying no growth for 12 hours, then you up the temp and it triples in the next 6-8 hours (18-20 hours total)? Sounds like your LM just isn't balanced properly at the moment. The yeast might be fine, but it seems the acidity balance is not quite right. Mine used to behave a lot like this - very unpredictable primo rises. Sometimes nothing in 12 hours, sometimes quadrupled (neither are good lol).
With panettone, it's almost always too much acidity in the LM. Even when your pH meter is telling you it's not acidic enough, it's sometimes too acidic 🙃
There was some talk recently on TFL that the hydration should be at least 50% for a dough pH meter to read right. I don't know the source of the statement. it was suggested to dissolve a sample in distilled water before measuring, IIRC. Maybe just working more water in to a small piece would do as well.
TomP
Yeah, I had actually reached out to Hanna Instruments a while back, asking for their recommendation for measuring pH in a stiff dough. Here's what they said:
I don't know about you, but...ain't nobody got time for that 😂
For any dough/levain/starter below 60% hydration you will struggle to get an accurate pH result.
I have a small pestle and mortar in the kitchen and put 3g dough in the mortar and add 20g deionised water in 2 lots, mushing things up with the pestle after each addition.
Then take the pH - I don't bother with any stand.
Lance
It is very hard to work with a LM as young as yours, as they tend to be quite acidic at the outset. I have also found that fruit-based cultures are the most difficult in this regard. You can introduce more diversity to your starter by giving it some higher ratio feedings, and you can control acidification of the primo by increasing the sugar in it (taking sugar away from the second impasto and putting it in the primo). Aim for a %Cu of 35 to 37.