Firepit

Firepit
(Building)
Location
Outside
Requirements
Pyrolysis 1
Cost to Build Firebricks 40 Slate 80

Warning: USING firepits causes Soot Pollution

A firepit allows for the safe burning of wood with the help of flint and tinder to start the fire. The residue of a firepit is charcoal. Fish and vegetables can be grilled over the fire. Additionally, some items can be burned in a firepit to produce ash or lime.

Sources

This building becomes available once you have learned the Pyrolysis tech and Pyrolysis 1. The Carving skill is also required for Tinder.

Cost

• 40 Firebricks
• 80 Slate

Built Outside (Self > Projects > Charcoal).

Upgrades

The Firepit can be upgraded to take Long Sharp Sticks as well as Sharpened Sticks for grilling food. This upgrade costs: This upgrade lets you grill 75 vegetables or fish at a time.

• 2 Bolt
• 5 Iron Bars

Use

• Produce Charcoal from 200 Wood.
• Add up to 20 of each type of Fish and Vegetables, except Leeks, to produce Grilled Cucumbers, Grilled Cabbage, Grilled Carrots, Grilled Garlic, Grilled Onions, Grilled Peppers, Grilled Watermelons, Grilled Fish, and Grilled Eggplant. You will need a Sharpened Stick for each type of food being grilled.
• Add up to 100 Leeks, 100 Dried Flax, and/or 100 Dried Papyrus to produce Ash.
• Add up to 100 Limestone to produce Lime.

Starting the fire

You need 1 Flint, 1 Tinder, and 200 Wood to start the fire. Note that if you intend to grill food, you need to add it to the fire BEFORE you light it. The flint is not consumed.

Each attempt to light a fire can:

• Succeed;
• Fail - you can try again immediately;
• Fail and consume the Tinder - you will need to add more before trying again.

Stoking the fire

Once a fire has been lit, you have the option of stoking it if you have a Sharpened Stick or an Iron Poker. If you have both, it will let you choose which to use. Both seem to act identically other than that the poker does not seem to have a chance to burn up. Stoking a fire correctly keeps it burning longer, which increases its charcoal, ash, and lime yields. Stoking does not affect Grilled Food yields.

A firepit runs through the following stages:

• A very dim warmup stage, immediately after lighting. Stoking the fire at this stage will put the fire out immediately and you will recover all materials except Tinder unburned.
• Burning merrily: a normal stage where the fire is orange. Stoking the fire at this stage will put it out, but not immediately - it will go to the "smouldering out" stage first. This phase can last for anywhere from 10 to 45+ seconds.
• Periodically, the fire will brighten then dim (orange -> yellow -> white -> yellow -> orange) over a period of 14–15 seconds. This period is a stoking phase. You must stoke the fire exactly once during this entire brightening sequence, and preferably before it goes from white -> yellow. If you correctly stoke the fire, it will continue burning and return to the previous "normal" stage at the end of this stage. Be careful you stoke the fire only once over the entire brightening sequence, otherwise it will quickly smolder the fire, decreasing the fire burn time by 6 minutes than if it slowly smoldered out. If you do not stoke the fire in time, it will slowly "smouldering out" over a period of 6 teppy minutes.

Stoking Tutorial Video

If you look at the center of the fire with a color picking program it is trivial to know when a stoke phase occurs. The Hue of a fire will be 60 during the no-stoke phase, and then the Hue will drop to 0 for the stoke phase.

• Smouldering out: The fire has gone out and the firepit is cooling. This stage takes approximately 6 Teppy Minutes (About 6:34 real time). You will get a message in Main ("Your firepit has smouldered out") when the fire finishes cooling. At this point, the final products are produced and can be taken from the firepit.

It is possible to leave the byproducts of firepit usage (charcoal, lime, ash) inside the firepit and still use it.

Other Tips

• When you first start, it is imporant not to panic—the flames are going to seem to fluctuate between the stages. What you are looking for are the times when it holds the color—long stretches of orange—a solid few seconds of yellow—the blinding white and so on.

• Wait for the Orange. You do your thing after orange—and after staring at orange for so long—the change to yellow/white is an obvious one and you can stoke.

• For record purposes, it helps to type the stoke number into main—so you can keep track of how many stokes you've done—and the approximate time spent.

Half-an-Eye Stoking Method

You can use the (pinned) firepit menu to help you track whether you've already stoked that cycle. This method allows you to keep half an eye on the firepit instead of watching like a hawk for the fire to change color.

Starting the fire:

1. Light the firepit and pin the menu. The menu should show an option to "Stoke the Fire" with your Iron Poker or Sharpened Stick.
2. Wait for the first time the fire turns white hot or yellow. Click the "Stoke" action, and notice that the "Stoke" menu item disappears.
3. The next time you see that the fire is deep orange, click on an empty spot in the pinned menu so that the "Stoke" menu item reappears.

Now that the fire is started, you only have to worry about the stoke cycle twice:

• If you look at the fire and see that it's dark orange, then click the pinned menu to make sure that the "Stoke" menu item is visible.
• If you look at the fire and see that it's yellow or white, check the pinned menu. It will be in one of two states:
  • If the "Stoke" option is available, click it.
  • If the "Stoke" option is not there, do not click anywhere on the menu. Now you can keep half an eye on the fire until it turns orange again.

In both cases, make sure to click the menu instead of using the Hotkey to stoke the fire.

Yield

The yield of a firepit depends on:

• The number of ingredients originally added.
• For lime, ash, and charcoal: the time (not number of stokes!) the firepit burned for.

Optimal load

The yield formula appears to involve some integer truncation. This means that you do not have to fully load the firepit to get maximum yield! The optimal loads for each resource are:

• n*16 Limestone (16, 32, 48, 64, 80, 96)
• n*40 Leeks (40, 80)
• n*20 Dried Flax (20, 40, 60, 80, 100)
• n*20 Dried Papyrus (20, 40, 60, 80, 100)

For example, if you have 20 limestone, add 16 to the firepit and keep the other 4. Adding 20 limestone will yield the same as adding 16. If you put less than 16 limestone in, you won't produce any lime.

This also means that you shouldn't fully load a firepit with maximum amounts of everything. Only load 96 limestone and 80 leeks, not 100 of each, and you will still get the same yield.

Sample yields

This table shows yields for a full firepit and stoking times up to 60 minutes. Note that the actual burn time will be approximately 6 minutes longer due to warmup/cooldown periods. This assumes that fires are allowed to smolder out naturally; prematurely stoking the fire out incurs about a 5-minute penalty.

stoking time (teppyminutes)	charcoal	lime from 96 limestone	ash from 100 dried flax	ash from 80 leeks	ash from 100 dried papyrus
-5 (stoking prematurely near beginning)	15	8
0	25	13	11	4	17
5	30	16	14	5	23
10	34	19	15	6	28
15	38	20	17	6	32
20	41	22	18	7	36
25	43	23	19	7	39
30	45	24	20	8	42
45	51	28	23	9	50
60	56	30	25	10	57

Vegetables and fish always yield 1 grilled food for every 1 ingredient, regardless of stoking time.

(Discussion of possible deviations from the formula/table moved to Discussion page.)

Yield Formula

These formulas match the test data (see the discussion page) very well, and were used to generate the above table.

 t = int( (burning duration in teppyseconds) / 30 )
 charcoal = int( t^(1/3) * 11 )
 lime from limestone = int( t^(1/3) * int(limestone/16) )
 ash from flax = int( t^(1/3) * int(flax/20) )
 ash from leeks = int( t^(1/3) * int(leeks/40) )
 ash from papy = int( t^(1/2) * int(papy/20) )

(Discussion about yield moved to the Discussion page)

My calc in T9 suggest 20 should be changed to 14 in the formula for Papy. 6.Dec.2019 /Catote

There is good yield above 60 minutes stoking time. I just completed 80 minutes on two fire pits. Neither pit was complete. I couldn't take it anymore. Each pit yielded: 98 Ash, 59 Charcoal and 32 Lime from 100 papy, 80 leeks, 96 Limestone and 200 wood. /Hapu