Edersheim Jewish background resources: still good or largely outdated?

The answer to your question lies in the available data. Absent archaelogical digs, and Qumran, there really is not much to work with from the literal 1st century (the NT as the exception). And even worse, where near-by writings do exist (eg Josephus, Mishnah, etc), it's difficult to geographically isolate Judeah from Galilee culturally.

A simple example is Nazareth: 'normally' artisans, carpenters, etc would find little work in a small poor village. So, is Jesus' family well-conversant with Sepphoris and roman/greek culture? If the sons of Thunder had a sizable fishing business with servants, would they not be conversant with roman taxation and customers?

The result is the necessity of re-hashing bits and pieces; how much re-hashing does your Bible study demand? Mine ... a lot. So I don't bother with Ebersheim (an opinion).

Francis said:

I own several of Edersheim's resources such as the Life and Times of Jesus the Messiah and Sketches of Jewish Social Life in the Days of Christ.

How extensively tagged are these works in Logos, may I ask?

Hello Francis,

In regards to John 2:6 the answer is relatively elementary and can be found in b. Ber. 53b; and Shabb. 62b. This is simply the standard ceremonial washing of hands (Taharot) before meals and prayer. Discussions of this can also be found in the standard reference work the Shulkhan Aruk Orakh Chayyim

The Jewish Annotated New Testament (link) by Amy-Jill Levine and Marc Zvi Brettler  may offer you some of what you are after. You might also enjoy using the up to date Encyclopaedia of Judaism (5 vols.) (link) in Logos and The much older Jewish Encyclopedia (12 vols.) (link) also in Logos.

Francis said:

I want to be able to look up -- for instance -- the ceremonial waterpots in John 2:6 and find specific discussion in relation to the passage as to what were the related customs.

I find background commentaries best for this sort of thing. The Zondervan Illustrated gives reasonable detail:

Nearby stood six stone water jars (2:6). The jars stood nearby—probably not in the dining room itself, but more likely in a passage near the courtyard near the well. There are six jars: In light of the significance the number seven has for John, the number six may connote imperfection as falling one short of the perfect number seven. The jars are made of stone, because stone was not itself considered to contract uncleanness. 

The kind used by the Jews for ceremonial washing (2:6). This practice may have involved the washing of certain utensils used at the wedding and the washing of the guests’ hands (cf. Mark 7:2–5; more broadly, John 3:25).

Each holding from twenty to thirty gallons (2:6). The original text reads “two to three metrētēs”; one metrētēs equals roughly ten gallons. This adds up to a total of one hundred and twenty to one hundred and eighty gallons for all six jars combined. A large number of wedding guests must be accommodated for the course of an entire week of festivities.

Another useful resource is the Eerdmans Dictionary of Early Judaism. It has a useful - and easy to find - article on Stone Vessels:

With obvious exceptions like tables and trays, stone vessels were designed to hold liquids. Literary sources (m. ʾOhol. 5:5; b. Šabbat 58a; John 2:6) indicate that they were regarded as unsusceptible to ritual impurity, along with vessels made of dung or of unfired earth (m. Kelim 4.4; m. Yad. 1:2; m. Parah 5:5). They were reportedly used at the Temple to mix the ashes created by the burning of the red heifer (m. Parah 3:2; 5:5).

The role of stone vessels in the purity system allows archaeologists to use their presence at a site as an indicator of Jewish inhabitants, and their widespread discovery in Galilee has played a major role in recent scholarly arguments that the region was predominantly Jewish. Some scholars, however, have downplayed their purity function, suggesting that their appeal was partly utilitarian, with their popularity due to sturdiness or stylistic trends.

Exactly when usage of stone vessels began is uncertain, but it clearly increased in the late first century B.C.E., when Herod’s renovation of the Jerusalem Temple resulted in increased quarrying of limestone. The phenomenon of their usage is thus related to that of stone ossuaries, which also began at that time. Fragments of stone vessels are very common in mid first-century C.E. strata, especially in destruction layers from the First Jewish Revolt, suggesting that this was the apex of their usage. Manufacture and usage dwindled after the revolt, apparently ceasing altogether by the mid-second century C.E. Some have suggested that their disappearance was due to a decreased emphasis on ritual purity in the wake of the Temple’s destruction; others have noted, however, that the Temple’s demise did not diminish the interest in ritual purity among the rabbis and many other Jews.
Stone vessels have been found in both urban and rural settings and in homes both large and small. Aside from more expensive large storage jars, kraters, and tables, which appear primarily in homes of urban elites, their usage seems to have cut across class lines. Misshapen or partially formed pieces, cores removed during the manufacture of jars, chips, and/or quarries attest to the presence of significant workshops at numerous sites including Jerusalem (the southwest corner of the Temple Mount, the “City of David,” Mt. Zion, the Jewish quarter, Mt. Scopus), Gethsemane, Jebel Mukkabar, Tell el-Ful, Hizma, and, in Galilee, Reina and Bethlehem. Lesser numbers of cores found at other sites indicate small-scale production by artisans.

The extent to which usage of stone vessels was associated with particular subgroups within Judaism is unclear. Priests had an obvious need to maintain purity, and many vessels, including some of the more expensive and elaborate forms, have been found in the homes of priestly elites in Jerusalem. Mugs and kraters have been found at Qumran, attesting to a place for them in that sect’s understanding of the purity system. Some scholars have suggested that the widespread use of stone vessels is an indication of the strength of Pharisaic influence; alternatively, Pharisaic preference for such vessels might merely reflect larger social trends. Perhaps many users of stone vessels identified with no particular sect or party. It is also possible that some Jews found no place within their understanding of the purity system for the innovation of stone vessels. Our sources are too limited to allow confident answers to such questions.

Searching a collection of background resources for John 2:6 also revealed an interesting section in The Purity Texts:

According to Jewish law, stone is insusceptible to impurity. It is not in the list of susceptible materials in Lev. 11:32–33; in fact the text explicitly states that cisterns are insusceptible to impurity (Lev. 11:36). Some scholars suggest that stone vessels are insusceptible because they are ‘entirely from unworked material’ (Regev 2000a: 230). In any case, since stone is insusceptible to impurity, both impure and pure persons can use the same vessel and not be concerned about the transfer of impurity. Even if an impure (dead) insect or carcass comes into contact with it, a stone vessel is still eligible for use since it cannot receive impurity.

The most important type of stone vessel is the kallal (calyx krater), the large jar used for storing food and liquids. It was used by the rich and required a complicated production technology due to its large size and decorative rims. John mentions six large stone vessels for Jewish purification rites, each holding 20–30 gallons (Jn 2:6) used for a wedding at Cana in the Galilee. These were no doubt kallal-type vessels (Regev 2000a: 232). In the Upper City of Jerusalem, Y. Magen has discovered a cave used as a workshop for the manufacture of stone vessels (Magen: 1988).

More significant than the kallal, at least for this study, are the stone measuring cups discovered in settlements outside Jerusalem, because they cannot be connected with priestly matters or pilgrimage during festivals. Many of these stone cups were found in the Judaean hill country, Judaean Desert, Samaria, Galilee, the Golan Heights and the Transjordan. As E. Regev says, ‘These finds attest that many Jews in smaller towns and the rural settlements actually maintained ritual purity … Enormous number of vessels … found in almost every known Jewish settlement in the Land of Israel, even the smallest … For example, in Iotapata (Iodphat), the Galilean town which Josephus claims fortified itself against Vespasian in 67 CE, at least 120 fragments of stone vessels were found’ (Regev 2000b: 232). These are not storage vessels but ‘small domestic mugs, pitchers, and bowls that contained drinks and food for daily meals’. If these were just for storing priestly contributions, larger vessels would have been needed. This wide distribution of common vessels for cooking and eating made from stone reflects the ‘everyday and common character of this maintenance of purity’ (Regev 2000b: 233). It is important to note that archaeologists found this multiplicity of stone vessels during the Herodian period, the latest being found during the Bar Kokhba revolt. Thus, it is in the Qumran era that a concern with stone vessels and purity in general is most apparent.

Significantly, 200 fragments of stone vessels have been found at Qumran (Regev 2000a: 234). Although Qumranites certainly regarded stone to be susceptible to impurity, H. Eshel has claimed that this susceptibility was limited only to those vessels coming into contact with oil (11Q19 49.11–16; CD 12.15–17; cf. War 2.123; H. Eshel 2000: 45–52, see above ‘Liquid’). Further archaeological support for purity at Qumran lies in the possible evidence of storage jars containing animal bones (see Appendix to Chapter 3, below; Magness 2000: 714). In sum, the archaeological data from both purification installations and food vessels found at Qumran supports the witness of the Scrolls that a sectarian community with a high standard of purity lived there during the Second Temple period.

For the time it was I think Edersheim was very good.Where he really shine is the balance of head and heart.