Is parched grain specially tamsik?
Assuming one knows the distinction between the three sadhakas (The 'Pashu', The 'Veer', The 'Divya'- see this answer).
For all sadhakas the PanchMakara is prescribed however it slightly varies due to the principles underneath. One of the PanchaMakara is 'Mudra'. The very first time one reads the word Mudra one might relate it to a perticular hand gesture similar to one found in Yoga, however it is has a different meaning in the context of PanchaMakara. The Sarvollāsatantram, 27th Ullhasa describes the Mudra-Lakshanam:
अथ मुद्रालक्षणम्- ब्रीहिणं भर्जितं प्रोक्तं शर्कराद्यैः सुवासितम् । योनिपद्मकदम्बेति लक्षणं परिकीर्तितम् ॥
Rice Roasted along with Sugar and Gandha(?) Is considered as Mudra, in terms of the YoniPadma(?) one uses Neolamarckia cadamba (burflower/ laran).
अन्यानि यानि द्रव्याणि भर्जितानि महेश्वरि । इति मुद्रा शोधिता चेत् देव्या: प्रीतिकरा परा ॥
O MaheshWari, other substances which are roasted, can make the Devi very happy after MudraShodhan.
धान्यं भ्रष्टं वह्लियोगैश्चर्वणीयं महेश्वरि । इति मुद्रा-कृता संज्ञा महामोदप्रदायिनी ॥
A cereal which is roasted over flame (Agni) which can be chewed is called Mudra. It has a good taste.
Both, Pashu and Veer Sadhakas stress upon the neccesity of five Ms. However they both have different Anuklapas. For the Pashu which perform the puja of devi, often called PashaChara (पश्वाचार) has the following MudraAnuklpa:
बिना लवणतोयाभ्यां भर्जित व्रीहिणं शिवे । मुद्रानुकल्पं परमे विभावस्य मतं पशोः॥
The opinion of Pashu is parched grain or rice cooked without water is the MudraAnukalp.
The Anukalp is specifically intended for Pashu thus must not be Tamasik.
For VeerBhava: its Chana or chickpeas.
मुद्राभावेडपि चणकं भर्जित॑ परमेश्वरि ॥