Making Turkish/ground coffee beverage on Shabbos:
Ground coffee is made through roasting and then grinding the coffee bean. It does not dissolve like instant coffee and has never before been cooked in water. This is in contrast with instant coffee which is made from dehydrated water that had ground coffee cooked in it, and thus dissolves when it reaches contact with liquid. The fact that ground coffee has never before been cooked and does not dissolve raises the Halachic question of whether one may make this coffee beverage on Shabbos using hot water, and whether one may filter the water from the undissolved ground coffee. Making the beverage using hot water can fall under the cooking prohibition, while filtering may fall under the Border prohibition. We will now analyze both of these aspects:
Mixing it with hot water:
Ground coffee which has never before been cooked in water is subject to the debate in Poskim regarding whether a prebaked or pre-roasted food may be cooked in a liquid on Shabbos, of which the final ruling is to be initially stringent like the opinion who rules that it contains a cooking prohibition. Thus, initially one may not place it into a Keli Rishon or pour onto it from a Keli Rishon, or place it into a very hot Keli Sheiyni, as it has ability to cook. Regarding a not very hot Keli Sheiyni that is above Yad Soledes, this matter is disputed in Poskim: Some Poskim rule that coffee is defined as a spice and may hence be entered into a not very hot Keli Sheiyni. Other Poskim rule that coffee is not defined as a spice and hence may not be placed into any Keli Sheiyni that is Yad Soledes, and it is to only be made with Iruiy Keli Sheiyni or Keli Shelishi. Other Poskim rule that ground coffee is similar to tea and is defined as Kalei Habishul and thus may not be made with any hot water that is Yad Soledes, even in a Keli Shelishi or Revi’i. Practically, the mainstream approach follows the second opinion and hence Turkish/ground coffee may be made on Shabbos using hot water by putting the coffee into a 3rd cup of boiling water [i.e. Keli Shelishi], or pouring the hot water into it from the 2nd cup [i.e. Iruiy Keli Sheiyni].
It is permitted to make a hot beverage of ground/Turkish coffee on Shabbos through using a Keli Shelishi or Iruiy Keli Sheiyni.
Filtering: Coming up in Part 2
 See Admur 318:12; Michaber 318:5; Some Poskim rule there is [a prohibition to] cook [a food] that has been previously baked or roasted, and [thus according to them] if one places baked or roasted [food] even while still burning hot into a Keli Rishon that is Yad Soledes, he is liable. [1st opinion in Michaber and Admur ibid; Yireim 274] However, other Poskim rule it is permitted to place a baked and roasted food, even if cold, even into a burning hot Keli Rishon, being that [according to them] there is no [prohibition to] cook [a food that has been] already baked or roasted. [2nd opinion in Michaber and Admur ibid; Rama 318:5; Ravayah 197]
 Admur ibid “It is the custom to initially be careful like the first opinion to not place bread even into a Keli Sheiyni so long as it is Yad Soledes.”; Rama 318:5
Ruling of Michaber: Some Poskim rule that according to the Michaber [See Shabbos Kehalacha 3:18 p. 168]
 Admur 318:11 regarding Keli Rishon’s cooking status, 318:12 regarding a pre-roasted food; Michaber 318:4
Definition of a Keli Rishon: A Keli Rishon is the original pot of food that was taken off the fire, or off any other heating surface [even if it’s content is no longer Yad Soledes].
 Admur 318:19 regarding Iruiy Keli Rishon’s cooking status, 318:12 regarding a pre-roasted food; Michaber 318:10; See Shach Y.D. 105:5
Definition: The pouring of the content of a Keli Rishon that is Yad Soledes onto a food or liquid. [Admur ibid]
 Implication of Admur 318:20; Tur 318; M”A 318:34; Levushei Serud ibid; Tzemach Tzedek Mishnayos 3:5; as explained in Ketzos Hashulchan 124 footnote 31; M”B 318:76; and 48; Chayeh Adam Shaar Mitzvas Haaretz 2:9; Rosh Yosef; See Shabbos Kehalacha 1:38 and 2:4
Other opinions: Some Poskim learn that the bath tub case is an exception and was only made forbidden due to a decree that one may come to heat up also in a Keli Rishon. Hence according to them a very hot Keli Sheiyni would have the status of a Keli Sheiyni. [Machatzis Hashekel 318:35, based on Rashi 42a; Toras Shabbos 318:27; See P”M 318 M”Z 18]
What is the definition of a very hot Keli Sheiyni which has the status of a Keli Rishon? If the Keli Sheiyni is much hotter than Yad Soledes Bo it retains the status of a Keli Rishon. [Ketzos Hashulchan 124 footnote 25] Some Poskim write it is the amount of heat that a person would scold his finger if he entered it into the water even for a moment. [Yad Nichvas Bo] [M”B 318:48 in name of Chayeh Adam; See Shevet Halevi 7:42]
 Igros Moshe 4:74-18 writes that coffee has the status of spices and he wonders at those who are stringent. Nevertheless, he concludes that one should not be lenient to place it in a Keli Sheiyni.
 See Admur 318:11-12; 19; M”B 318:65 and 34; Mishneh 42a; See Michaber 318:9-10 that only prohibits a Keli Rishon
 Ginas Veradim 3:2; Beir Heiytiv 318; Shaareiy Teshuvah 318:14; Chasam Sofer 74; Or Letziyon 2:30; Shabbos Kehalacha Vol. 1 p. 54
 Admur 318:12 “Accordingly, even regarding [placing these foods] into a Keli Sheiyni one needs to be stringent Rabbinically. One therefore needs to be careful not to place baked bread even into a plate [of food] that is a Keli Sheiyni so long as it is Yad Soledes.” M”A 318:18; M”B 318:42; Some of these foods carry a Biblical cooking prohibition, while others are Rabbinically forbidden due to it appearing like cooking. [see Admur ibid]
 Admur 318:11; Michaber 318:4
 Peri Megadim 447 A”A 9 [See however Shabbos Kehalacha ibid in Biurim for other areas that the P”M is stringent]; M”B 318:47 based on P”M ibid quotes in a number of places; Ketzos Hashulchan 124 footnote 52; Nimukei Orach Chayim 318 regarding salt; Igros Moshe 4:74; Sheivet Haleivi 7:42; and many other Poskim; See Shabbos Kehalacha Vol. 1 p. 80-82
Other opinions: Some Poskim rule it is considered like a Keli Sheiyni itself, and hence all foods that are forbidden to be placed in a keli Sheiyni would likewise be forbidden in a Keli Shelishi. [Yereim p. 134; Shevisas Shabbos Mevashel 23 based on Chasam Sofer; Chazon Ish 51:17] Practically, the custom is like the lenient opinions which hold that it is allowed to place into it all foods which are allowed to be poured on from a Keli Sheiyni. However, since there are opinions which are stringent by a Keli Shelishi, therefore when applicable one should rather pour onto the foods from a Keli Sheiyni than to place them into a Keli Shelishi, being that the pouring of a Keli Sheiyni is explicitly permitted by all. [Shabbos Kehalacha ibid]
 Piskeiy Teshuvos 318:36 that since today people no longer eat the ground coffee, it has the same status as tea of which many Poskim rule that it may not be made at all on Shabbos using hot water. [See M”B 318:39; Aruch Hashulchan 318:28; Bris Olam Ofeh 23; Az Nidbaru 3:23-24; Piskeiy Teshuvos 318:36] Vetzaruch Iyun as coffee is prebaked and is a dispute if it has a cooking prohibition even in a Keli Rishon, and thus even those who are stringent by tea have room to be lenient by ground coffee.
 This especially applies for those who allow making tea on Shabbos and do not suspect for it to be Kalei Habishul. [See Peri Megadim 318 A”A 35; Implication of Tzemach Tzedek Mishnayos 41, as explained in Shabbos Kehalacha Vol. 1 p. 51-52; Implication of Maharam Shick 132, Rav Lavut in Haaros to 318:12; Ketzos Hashulchan 124 footnote 21; Minchas Baruch 12; Igros Moshe 4:74-15 [Keli Shelishi]; Or Letziyon 2:30-3; Divrei Shlomo 2:153 ;’Nishmas Hashabbos 2:29; Menuchas Ahava 2:10-39; Shabbos Kehalacha Vol. 1 p. 80-82]