Tar Distillation

A Valheim mod that adds a second way to get tar: burn it out of resinous pine wood, the way Norwegian tar burners did it. The plains tar pits are untouched — you can still go and farm them, this is just the other option.

The chain is deliberately gated behind the blast furnace, which needs an artisan table and therefore Moder. You cannot reach tar this way any sooner than you could have walked into the plains and taken it.

The chain

Step	Station	In	Out
1. Split	Artisan table	10 core wood + 5 resin	1 Tyrispik
2. Dry	Blast furnace (burns coal as usual)	1 Tyrispik	1 Dried Tyrispik
3. Burn	Fermenter	1 Dried Tyrispik	6 Tar + 2 Coal

One full run is a fermenter cycle, so roughly 40 minutes of real time per batch, and you scale it by building more fermenters — the same way you scale smelters.

Everything in that table is configurable; see Configuration.

Why these steps

From Tjærebrenning on Norwegian Wikipedia, the real process was:

• Tyri — the resin-soaked kjerneved (heartwood) and roots of pine. The best came from stumps that had stood 10–15 years or more, until the soft outer wood had rotted off and only the pitch-soaked core was left. In game that is core wood, which is literally the heartwood of pine, plus resin.
• Spik — the stump wood was cleaned, coarse-split, then fine-split into spik, sorted and stacked to dry. The article notes this preparation alone could take up to a man-year of work. That is step 1 and step 2 here.
• The mile — the dried spik was stacked in a funnel-shaped tjæredal lined with birch bark, covered with turf, and lit so it smouldered with as little air as possible. Tar melted out and ran down a hollowed log to be collected. The fermenter stands in for the mile: a covered vessel that works slowly and is tapped at the bottom. The small version, the minimile, burned for about half an hour — close enough to a fermenter cycle that the timing needs no apology.
• Charcoal — "store mengder trekull blir igjen etter brenningen og er verdsatt." A burn leaves a lot of valuable charcoal behind, so tapping the fermenter gives coal along with the tar. It roughly pays back what the blast furnace burned to dry the wood, which is the same loop the tar burners were in.
• The yield — tar was 20–25 % of the dry weight of the wood; about 1 m³ of pine (~280 kg) gave some 60 kg, around 50 litres. The default of 6 tar per batch keeps roughly to that fraction of what goes in.

What is deliberately not modelled: the fractions. Real tar was tapped in layers — thin watery turpentine first, then acidic tjærelóg, then clean tar at the bottom — and the burner read the smoke colour to steer the temperature. That is a mini-game, not a recipe, so the fermenter just hands over finished tar.

Install

Needs BepInExPack Valheim and Jotunn.

One package covers players and dedicated servers: install it with a mod manager, or unpack the zip and copy its BepInEx folder over the game or server root. Steps for both are in package/INSTALL.md.

Multiplayer

The mod adds items, so it is marked EveryoneMustHaveMod with VersionStrictness.Minor:

• Install it on the server and on every client, at the same version. A client without it will be refused, which is the point — the alternative is a client that cannot resolve the item prefabs.
• The server's config wins. Every setting is admin-only, so Jotunn locks the entries on clients and pushes the server's values down as part of the connect handshake. You only have to keep the server's config file correct.
• Amounts (Core wood per batch, Resin per batch, Tar per batch, Coal per batch) are applied to the live recipe and the fermenter when they change, so a synced value takes effect without a restart. Fermenters that are already placed and loaded keep the yield they were built with until their zone reloads.
• The two station settings are read once at startup and need a restart on every machine. Do not change those mid-session.
• Tapping is handled by the fermenter's owner only — vanilla checks that before it schedules the tap — so the charcoal cannot be duplicated by a second player standing at the same fermenter.
• On a dedicated server the items are built from an ObjectDB.Awake prefix as well as from Jotunn's usual vanilla-prefabs event. That event hangs off ObjectDB.CopyOtherDB, which in the client build only the main menu calls, and a headless server is a different build of the game — so the content is registered either way rather than on an assumption.

Configuration

BepInEx/config/hakon.valheim.tardistillation.cfg

Section	Setting	Default	Notes
1 - Splitting	Splitting station	ArtisanTable	Restart required
1 - Splitting	Core wood per batch	10	Live
1 - Splitting	Resin per batch	5	Live (0 removes it, but only after a restart)
2 - Drying	Drying station	BlastFurnace	Restart required. Smelter or CharcoalKiln make the chain reachable earlier
2 - Drying	Drying seconds	0	Live. 0 = the station's own speed
3 - Burning	Tar per batch	6	Live
3 - Burning	Coal per batch	2	Live, 0 turns the by-product off
3 - Burning	Burning seconds	0	Live, including on fermenters already running. 0 = the fermenter's own duration

Both timers only apply to tyrispik: ore in the same blast furnace still smelts at its normal speed, and mead still ferments at its normal speed. Vanilla keeps one timer per station rather than per recipe, so this is done by patching the clock for our item only — Smelter.m_secPerProduct is swapped in for the single update call that is working on a tyrispik, and the fermenter's elapsed time is scaled so it crosses the station's finish line at the configured moment.

Station names are Jotunn's, so the config file lists the valid values for you.

Building

Needs the .NET SDK. Valheim, BepInEx and Jotunn supply the references, so the paths in TarDistillation.csproj must point at a real install:

dotnet build

Defaults to the Steam install under C:\Program Files (x86) and the Thunderstore profile HWandMT, and copies the built DLL into that profile's BepInEx/plugins. Override either:

dotnet build -p:ValheimDir="D:\SteamLibrary\steamapps\common\Valheim" -p:ProfileDir="..."

Packaging

.\pack.ps1

Builds Release and writes one archive to dist/: TarDistillation-<version>.zip, with manifest.json, icon.png, README.md and INSTALL.md at the root and the plugin at BepInEx/plugins/TarDistillation/TarDistillation.dll. That is the layout Thunderstore takes on upload, the layout mod managers import, and the layout a server root already has, so the same zip serves players and the server.

Entry paths are written with forward slashes, so unzip on a Linux server builds the folder tree instead of one oddly named file.

BepInEx and Jotunn are dependencies and are not bundled.

Status

Compiles clean against Valheim build 25909357, BepInEx 5.4.2351 and Jotunn 2.30.2, and every game and Jotunn API it touches was checked against those assemblies. It has not been run in-game yet — that is the next step, ideally on a second profile before it goes near a live world.