From SelectioNaturel:

“Arnaldo always tinkered with making his own wines.  He has a tiny plot that he farms with diligence, often using biodynamic preparations and simple hand tools.  I would describe the size of the vineyard as "garden size" - very small but handled with absolute care.  His passion for natural wine is deep, so the small amount of wines he makes are pure as can be.  Sangiovese is at the heart of course, with Trebbiano, Malviasia and the occasional other grapes like Malvasia Nera, Aleatico, etc. 

For many years Arnaldo made his wines in the corner of Marco Tanganelli's winery.  In the past 2 years Arnaldo has completed his own tiny cantina, where he now makes his wines.  He uses a combination of old oak barrels, stainless steel, resin and anfora for vinification and aging.  All the wines are made with natural fermentation and without sulfur additions when possible.”

Links to more info about Arnaldo Rossi: