It's often said that China had a sino-centric view of the world and anyone who was not Chinese was automatically considered a barbarian.
But I read recently that Europeans before the 18th century usually didn't use forks, and would instead cut their food with a knife and eat it with their hands. For Chinese people who've been using chopsticks for centuries, assuming they held the notion that eating with your bare hands is barbaric, that would certainly make Europeans seem like barbarians.
So basically, did Chinese people mention any specific Europeans dress, behavior, appearance, food, language, culture, etc. as seeming "barbaric"?
I believe your question stems from debate regarding the precise definition of the Chinese term 夷 (yi) which appears to have arisen in the mid-19th century. This term was variously translated as 'foreigner' or 'barbarian' - the latter use promulgated by a Pomeranian missionary-cum-translator in China in the early 19th century, the former championed by Waley (1889-1966) and earlier documentation provided by individuals ranging from Matteo Ricci (1552-1610) to British envoy George Macartney (1737-1806) - which made no note of yi as a perjorative.
Additionally the Qing Chinese stressed that yi merely designated foreigners deemed as 'easterners' (the British most regularly visited Eastern ports), with man designating southern foreigners, rong northerners, and so forth. The British interpreted the term as highly offensive and showing of contempt - and indeed the term did have currency as a frequent distinguisher of Chinese culture from outsiders - the extent of distaste it showed for the latter being the subject of bitter discourse.
Indeed the issue of yi coloured relations between Britain and Qing China to such a degree that article 51 of the Anglo-Chinese Treaty of Tianjin (1858) specifically addresses its use, prohibiting its official use in reference to the British government (with a translation of the article here). Historian Lydia Liu writes "Never has a lone word among the myriad languages of humanity made so much history as the Chinese character yi." There is certainly an argument that the supposition of yi as a strict pejorative by the British served as perfect reasoning for diplomatic aggression British policymaking showed in the country at the time.
Qing attitudes towards foreigners in reality were much more varied. Initial official opinion of Europeans was born of naivety - they were not seen as any more powerful or influential prior to the 19th century than traders who had been visting China for over a millennium. Their customs and produce were mere curiosities at best to the emperors of the late Ming and early Qing and not considered dangerous or influential with regards to imperial authority. Contrary to popular opinion, Chinese opinion was not cemented in opposition to European aggression even after the Second Opium War (1856-1860) - a marked negative trend in Chinese attitudes towards Europeans was only really noticeable in the period surrounding and subsequent to the Sino-French War of 1884-1845 by which point Western intentions became clear for all to see and the dynasty was seen as in peril.
Even at this point amongst opposition there was an ingrained psychological phenomenon in Chinese society which pinned much blame on the Qing for the inability to successfully govern and modernise at the rise of European imperialism - providing a fatal weakness that it would be natural for foreigners to exploit. Whilst some by this point proclaimed of "selling my soul to the foreign devil" (Lu Xun, 1890s), others equally became open critics of the Qing regime in a brazenness rarely seen prior. Whilst the last Qing emperors placed great importance on the understanding of foreign society and technology, openly praising Western methods became taboo and individuals such as the pro-Western Qing ambassador to London of the late 19th century was physically assaulted, impeached and finally dismissed for his opinions. "He cannot serve human beings / So how can he serve demons?" read one proclamation.
The zenith of anti-European sentiment in China would be reached with the Boxer Rebellion of 1899-1901 - a nationalist movement strongly opposed to Western imperialism and the strangehold the West had on China by this point - and unofficially supported by the Qing regime. The arrival of troops of the Eight-Nation alliance under a humanitarian guise and the effective complete subjugation of imperial power it resulted in imprinted a lasting stigma in Chinese sentiment towards the West which continued to exist to a greater or lesser extent throughout the 20th century. Whilst it would be unreasonable to surmise that the Chinese showed no contempt for Westerners prior to imperialistic designs on the Qing empire [indeed the superiority of Chinese culture generally had been a core tenant of dynasties of past], there is certainly a strong argument that this merely served as justification for otherwise what was clearly Western expansionist aggression towards Qing China beginning with policy-making leading up to the First Opium War (1839-1842) and arguably only ending with the dissolution of the empire in 1912 - throughout which anti-Western sentiment amongst the populace of Qing China would truly root itself.
Sources:
The Opium War - Julia Lovell
The Clash of Empires - Lydia Liu
China: A History - John Keay
Haven't most cultures considered other cultures barbaric at one time or another? Maybe this is more of a social science question?
Barbaric has very specific connotations for that time period. It was less about primitive and more about different. The ancient Greeks called the Persians barbarians despite the fact that they were a far far more developed and wealthy state