While Sur Lattes is illegal, it does still go on to some degree and it isn’t just large producers who do it; I’ve heard more rumors of small folks doing it lately. When it is done, it is normally on an entry level NV cuvee that is higher in volume. You aren’t going to see Sur Lattes in a DP, Cristal, Comtes, etc… Remember that Sur Lattes is Champagne normally undisgorged that is then sold to someone else, disgorged, dosaged, labeled and then sold. Usually this means the wine needs to be a traditional/common Champagne bottle shape and color - you never really plan to go the Sur Lattes route or know exactly where you are going to get wine from when the need arises.
There actually is a legal way to go the Sur Lattes route - you can purchase bottled Champagne made by someone else as long as you give it a unique label and register it properly or if you purchase/inherit old stock as part of an estate/winery sale. J de Telemont, Diebolt-Vallois, and Bereche are all examples of this.
As for what is most common in the negociant world of purchasing from growers/co-ops - they purchase grapes, juice, and wine. It really depends on what facilities the negociant has in the area. If they have their own press house, it will be just grapes. If they have a winery close by, they may buy the grapes, possibly give direction on pressing, and then take over the juice. In some cases, they will buy the finished first fermentation wine if that is the only or preferred way to make it work (though they technically are still paying for and buying the grapes - they just get the end product of wine).
The big houses are often blending it and most of the time they are not using it in the top end wines. Most of it will go into NVs; some will get into vintage, and even less will make it into a prestige wine. Most negociant NVs are not terribly exciting.
The negociants can buy whatever grapes/juice/wine they want and put it into whatever bottling they want, but for the best vintage and prestige wines (the ones we all talk about and drink) they really try and focus on their estate vineyards for a large majority of the wine. DP doesn’t have to buy in anything to make 5M bottles of top notch wine. They will use some purchased grapes if the quality is there, but they don’t have to. My point is that with top wines, the focus really is on quality and if you can purchase some grapes that might be better than what you have then why not.
As for the top co-ops, Devaux (label for the Union Auboise co-op) is another good one. I don’t find them as reliable and high in quality as Palmer or Mailly, but they make good wine. As for Palmer, it started out in Avize and later moved to Reims as most of its members were from the Montagne de Reims. They were always a group that was focused on quality from the top villages. At one point, I think you needed to be in a Premier or Grand Cru village to join, but that is no longer the case. Still, they are selective about who can join. They have a good lineup of Champagne and also a really large selection of older vintages. From what I have heard, when Sur Lattes was much more common, they were the go-to co-op for high quality NV (and some Vintage) bottles.
![[cheers.gif]](/uploads/db3686/original/2X/0/0ff9bfcdb0964982cd3240b6159868fbdf215b1a.gif "cheers"){kind=small}