Andhrímnir
lætr ield hrimne
Sæhrímni foðin,
fleska bezt;
en þat fáir vitu,
hvat einherjar alask.  

Andhrimner speedily returns:
The fire beneath Eldhrimner burns:
Sæhrimner  smokes in floods below ---
The best reflection heroes know.
Few think how many warriors dine,
From off his wide extended chine.

These are the homes where the powerful Aser dwell,
Andhrimner from Eldhrimner bringeth forth
Saehrimner, seethed,—most excellent of meats—
And few can tell how many Einheriar feed
Thereon.

18. Andhrimnir makes,
in Eldhrimnir,
Sæhrimnir to boil,
of meats the best;
but few know how many
Einherjar it feeds.

22. There Sooty-face boils in Sooty-flame
the boar called Sooty-black ;
'tis the best of fare, which few have heard
is the chosen warriors' food.

18. In Eldhrimnir         Andhrimnir cooks
Sæhrimnir’s seething flesh,-
The best of food,        but few men know
On what fare the warriors feast.

18. By Andhrimnir in Eldhrimnir
Saehrimnir, the boar, is boiled,
the best of bacons;    though 'tis barely known
what the einherjar eat.

18. Sooty-Face in Sooty-with-Fire,
Boils Soot-of-the-Sea:
To the Battle-slain boar's flesh
Was ever the finest fare.

18. Andhrimnir has Sæhrimnir boiled
in Eldhrimnir,
The best of pork, but few know
By what the Einheriar are nourished.

18. Sootfree makes boil
in Sooty from the Sea,
finest of bacon,
but few men know
what the elect fighters are fed on.

2011 Andy Orchard
The Elder Edda: A Book of Viking Lore
'The Lay of Grimnir"

Gylfaginning 38:
 
Then said Gangleri: "Thou sayest that all those men who have fallen in battle from the beginning of the world are now come to Odin in Valhall. What has he to give them for food? I should think that a very great host must be there." Then Hárr answered: "That which thou sayest is true: a very mighty multitude is there, but many more shall be, notwithstanding which it will seem all too small, in the time when the Wolf shall come. But never is so vast a multitude in Valhall that the flesh of that boar shall fail, which s called Sæhrímnir; he is boiled every day and is whole at evening. But this question which thou askest now: I think it likelier that few may be so wise as to be able to report truthfully concerning it. His name who roasts is Andhrímnir, and the kettle is Eldhrímnir; so it is said here:

Andhrímnir | has in Eldhrímnir
Sæhrímnir sodden,
Best of hams; | yet how few know
With what food the champions are fed."

Then said Gangleri: "Has Odin the same fare as the champions?" Hárr answered: "That food which stands on his board he gives to two wolves which he has, called Geri ("Ravener") and Freki ("Glutton, greedy"); but no food does he need; wine is both food and drink to him; so it says here:

19. Geri and Freki | the war-mighty glutteth,
The glorious God of Hosts;
But on wine alone | the weapon-glorious
Odin ever liveth.

The ravens sit on his shoulders and say into his ear all the tidings which they see or hear; they are called thus: Huginn ("Thought") and Muninn ("Memory"). He sends them at day-break to fly about all the world, and they come back at undern-meal; thus he is acquainted with many tidings. Therefore men call him Raven-God, as is said:

20. Huginn and Muninn hover each day
The wide earth over;
I fear for Huginn lest he fare not back,--
Yet watch I more for Muninn." 

The Valhall Verses

Grimnismal 18 ff. enters into a long exposition on Valhalla and the things found there. The verses are among the most cryptic in the poem, suggesting that “hidden” or “mysterious” knowledge may lie concealed here. Can the intended meaning or meanings still be teased out of the poetry? It’s worth a shot. There is relatively little commentary on this poem, and less so in English. So in many ways, we’re entering uncharted (or at least uncertain) territory.

2011 Ursula Dronke, Poetic Edda, Volume III:

“18 opens like a child’s guessing-game: if Hrímnir implies ‘covered in soot’, Andhrímnir can mean ‘Without soot’ (cf. Vigf. s.v. AND-) and signify the spotless Sun. Eldhrímnir, as ‘Sooty on the Fire’ can be the soot-covered cooking-pot on the fire of the Sun (cf. 42). Sæhrímnir is ‘best of bacon’, we are told; it can be a black (i.e. wild) boar coming out fo the ocean to be cooked by the Sun. The ‘black boar’ is the sooty Earth, the provider of food. If the Boar-Earth is food for the living, what do the dead champions sustain themselves on? How can they exist?. “I have based this reading of 18/3-4 on the only myth I know that could relate to Sæhrímnir. It is the Indian tale of Vishnu in his Boar Incarnation carrying the goddess Earth up from the depths of the ocean (Zimmer 17f, 77f; PE II 115). Unfortunately, the goddess Earth is not the Boar, but as Zimmer says (78), ‘The boar is a warm-blooded animal belonging to the earthly sphere, yet revealing in swamps, and familiar with the watery element. Vishnu in this form plunged into the cosmic sea…gathered into his arms the lovely body of the still youthful Mother Earth, and while she supported herself by clinging to his tusk, brought her up again to the surface of the sea.’ Perhaps there has been a simplification of this tradition leading to 18/3-4; or there is no connection at all.”

 
Viktor Rydberg, in Our Fathers' Godsaga, 1887, writes:

"Andhrimnir (Andhrímnir). In the poem Grímnismál, a verse reads: “Andhrimnir in Eldhrimnir cooks Sæhrimnir, the best of meats—which ‘feeds’ the einherjes.” One can draw the conclusion that Valhall has a cook named Andhrimnir, and that in an actual kettle named Eldhrimnir, he cooks a real boar, Sæhrimnir, whose flesh serves as the einherjes’ food. And for Sæhrimnir to be used for this purpose day after day, one might further assume that it had the same quality as Thor’s goats so that, after it was butchered, it lived again (see Snorri’s Edda). All this is based on a misunderstanding. Into the poem Grímnismál are interpolated verses from an old song that is thoroughly mixed with symbolic imagery; for example describing death and sleep (Dáinn and Dvalinn) as harts in Yggdrasil’s crown, the bridge Bifröst as a fish (since bridgeheads are known as “fish-tails” in Icelandic), Yggdrasil with its mead-saturated crown of leaves as a goat from whose udders the mead flows, as drink for the einherjes, etc. Symbolic too are Andhrimnir, Eldhrimnir, and Sæhrimnir, as N. M. Petersen in his Mythology has already observed. The names’ common suffix –hrimnir refers to hrim (rime), “the first and finest transformation from buoyant to solid form.” The names’ prefixes And- Eld-, and Sæ- (Spirit-, Fire-, and Sea-) report in the clearest manner that the skald meant the elements air, fire, and water and thereby meant to say that only the finer elements, not the earth-matter, are incorporated into the einherjes birth."

In Grimnismál 18, we learn that the heroes of Valhalla, the Einherjar, are fed on the meat of an ever-renewing boar, Saehrimnir. Snorri informs us that “there will never be such a large number in Valhall that the meat of the boar called Saehrimnir will not be sufficient for them. It is cooked each day and whole again by evening.” (Gylfaginning 38). In Hrafnagaldur Óðins 19, the same boar is said to feed the entire company of gods. Similarly the Einherjar drink the ever-flowing milk of the goat, Heidrun (v. 25).

In Saehrimnir, we find a parallel to Thor’s goats, which can be slaughtered and eaten, so long as the bones are placed whole on the hide, and the heap hallowed by Thor’s hammer. The boar, like the goats, are ever renewing sources of meat. Saehrimnir feeds the heroes in Valhalla, who themselves are killed and come back to life. Thus the boar is like the warriors themselves— and ever renewing supply of “flesh”

Thor’s goats perform the same function:

Gylfaginning 44

“Öku-Thor drove forth with his he-goats and chariot, and with him that Ás called Loki; they came at evening to a husbandman's, and there received a night's lodging. About evening, Thor took his he-goats and slaughtered them both; after that they were flayed and borne to the caldron. When the cooking was done, then Thor and his companion sat down to supper. Thor invited to meat with him the husbandman and his wife, and their children: the husbandman's son was called Thjálfi, and the daughter Röskva. Then Thor laid the goat-hides farther away from the fire, and said that the husbandman and his servants should cast the bones on the goat-hides.
"Thor tarried there overnight; and in the interval before day he rose up and clothed himself, took the hammer Mjöllnir, swung it up, and hallowed the goat-hides; straightway the he-goats rose up…

Gylfaginning 38

Then said Gangleri: "Thou sayest that all those men who have fallen in battle from the beginning of the world are now come to Odin in Valhall. What has he to give them for food? I should think that a very great host must be there." …But never is so vast a multitude in Valhall that the flesh of that boar shall fail, which is called Sæhrímnir; he is boiled every day and is whole at evening.


When the einherjar aren’t feasting they amuse themselves by fighting. They ride out into the courtyard every day and fight until they cut each other into pieces. When mealtime comes they recover from their wounds and return to feast in Valhalla.

Snorri says:

42. "A mighty band of men must be in Valhalla," said Gangler, "and methinks Odin must be a great chieftain to command such a numerous host. But how do the heroes pass their time when they are not drinking?"
"Every day," replied Har, "as soon as they have dressed themselves they ride out into the court (or field), and there fight until they cut each other to pieces. This is their pastime, but when meal-time approaches they remount their steeds and return to drink in Valhalla. As it is said:—

'The Einherjar all
On Odin's plain
Hew daily each other,
While chosen the slain are.
From the fray they then ride,
And drink ale with the Aesir.'

The heroes like the goats regenerate. In this sense they are one. So with this in mind, let’s look at the words of the verse:

18. Andhrímnir
lætr í Eldhrímni
Sæhrímni soðinn,
fleska bezt;
en þat fáir vitu,
við hvat einherjar alask.

Saehrimnir is called “fleska bezt,” literally the "best pork". In other Germanic dialects “flesk”, however,  refers to meat in general (“flesh”). But in Old Icelandic, the Cleasby, Vigfusson Dictionary defines the word “fleski” as:

FLESK (fleski, Rm. l.c.), n. [A. S. flæsc; Engl. flesh; Germ. fleisch; not in Ulfilas; in Icelandic and all northern languages kjöt (Swed. kött, Dan. kjöd) is the common word, and flesk is only used of pork or bacon; Dan. flæsk; Swed. fläsk] :-- pork, esp. ham and bacon, often used in pl.; fán fleski, Rm. 29; fleska bezt, Gm. 18; forn fleski, Snót 226; brauð ok lítið fleski, Bs. i. 819; galtar flesk, Edda 23; hveiti ok flesk,

Even if limit the word “flesk” to mean only pork, we are not hindered in understanding it as a symbolic representation of human flesh, since all over Germania warriors are associated with boar symbols. Throughout Anglo-Saxon art and literature, boar imagery proliferates. Boar-plates and crests adorn several heathen era Anglo-Saxon helmets, and are described in the poem Beowulf. In Tacitus’ Germania chapter 45, those Germanic tribes who revere “the mother of the gods” carry her emblem, the boar, into battle to protect themselves. In Hyndluljod, Freyja rides her lover Ottar (Oðr) in the shape of a golden boar. Thematically, the poet connects him to Saehrimnir, in that he has the witch Hyndla liken Freyja to Valhalla’s she-goat: “running hot at night, like Heidrun among the he-goats” (v. 48). Heidrun is the nanny-goat which supplies the einherjar with ever-flowing mead (cf. Thor’s he-goats which yield an ever renewing supply of meat).

Freyja rides Hildsvini
by Luwig Pietsch 1860

The dwarves Brokk and Sindri make the golden boar Gullinbursti for Frey. Freyja, who names her boar Hildsvini, “battle-swine”, says that he was made for her by the dwarves Dainn and Nabbi (v. 7). Of interest here, one interpretation of Völuspá 10, informs us that dwarves also create the bodies of men (manlikur). The witch Hyndla perceives that the boar is actually her lover Ottar (Oðr) transformed, “on the way of the slain.” (v. 6, 7, 8). Freyja herself confirms that they are on the way to Valhalla (v. 1). Besides its usually meaning, the word “ride” also has a sexual connotation. Riða can also refer to sexual intercourse. When Freyja's lover is likened to a boar, it should come as no surpise that Snorri informs us that one of Freyja’s names is Sýr, “sow”.

The boar is a symbol of virility. a main attribute of Freyja’s brother Freyr is the boar. According to Skáldskaparmál 35, the primeval artisans Brokk and Sindri give Freyr the golden boar called Gullinbursti or Slidrugtanni. Gullinbursti (‘Golden Bristles’), Snorri says, can run across sea and sky by day or night faster than any horse. Its golden bristles radiate such brilliance that it was never dark wherever it went. According to the poem Husdrapa, Freyr, the god of fertility, rode this boar to Baldur’s cremation. According to Voluspa, Balder too will return from the dead, in time.

In Hyndluljod, the boar is, in fact, a transformed warrior on the way to Valhalla ; he is Freyja’s lover and thus her ‘ride’ (a sexual pun); likewise a boar is the food of the Einherjar (the heroes of Valhalla). So it would seem, at the very least, we have some poetic play of words here, perhaps meant to mask a mystery of the ancient heathen religion.

The boar symbolizes the ever renewing generations of human flesh. The “best of meats” is human flesh. Human flesh “feeds” the einherjar. It increases their number. In the next verse, we are told that Odin does not eat this meat, but instead feeds it to his wolves. “Food of wolves” is a kenning for warrior, as is “food of ravens”— animals sacred to Odin. Thus, the verse seems to suggest that the best “pork” or “flesh”— that which feeds the Einherjar— is equivalent (if not identical to) the ever renewing supply of warriors (i.e. human flesh), who die in battle day after day since the beginning of time.

In Gylfaginning, Snorri says:

39. "If it be as thou hast told me," said Gangler, "that all men who have fallen in fight since the beginning of the world are gone to Odin, in Valhalla, what has he to give them to eat, for methinks there must be a great crowd there?"
"What thou sayest is quite true," replied Har, "the crowd there is indeed great, but great though it be, it will still increase, and will be thought too little when the wolf cometh.