[Stronghold 21, Game design] Iron bottle neck- cause and iron farming

[Stronghold 21, Game design] Iron bottle neck- cause and iron farming


Click for background

Emblems and iron

Emblems require clumps of iron. You cannot unlock 1/10 of a class node. I had 6x 4*+14 heroes unlock nodes the same day. This was a huge drain on my iron.

Two builders and food

Stronghold 23 is not being released. You cannot work on several Advanced Buildings Level 2 at the same time like you could with regular buildings.

Before Stronghold 21, when low on iron, but hoards of food, you could work on any of your four regular mines, and the watchtower, all of which used food. But you cannot upgrade your watchtower past level 20 and you can only currently work on one Advanced Mine at a time.


Advanced buildings taking 10 seconds to convert. But take more than 10 seconds of iron production. This is causing a bottle neck for two builders.

Single builders can switch to upgrading Advanced Mine with food while they wait for iron production. One of the times second builder is severely hampered.

5* Battle items

Originally I was going to upgrade Advanced House to Level 9, highest possible with 5x Iron Storage Level 20. This would give me 5 recruits per hour.

But my alliance has decided to use harpoons. Now I need the iron to build Lodge Level 4. This unlocks Titanium shields, and Panacea, the only 5* battle items useful against triple bosses like Sand Empires or Grimforest.

After I unlock Lodge Level 4, I will have to construct at least 1 Harpoon per day. This takes iron.

Food Hoards

You can hoard food in training camps. There is no way to hoard iron.

Raiding for iron

The Devs nerfed raiding for iron, and food, ( see notes )

Iron bottle neck

All the above is causing an iron bottle neck for Stronghold 21. This may, or may not, be a deliberate design choice. It may also just be an unintended consequence of the Advanced Building design.

Iron farming

Season 1, province 17, stage 1 ( stage 1.17-1 ) has 1510 iron per WE, but only 1.4 recruits per WE.
Stage 2.15-9N has 1193 iron per WE and 2.857 recruits per WE but I cannot auto play it.
Stage 1.7-7 has double Rugged clothes, but only 1017 iron per WE.

So currently I am alternating between:
Stage 1.12-9 with 1388 iron per WE, 2.5 recruits per WE, and I can auto play with 3* heroes. This has 9 to 11 monsters for 3 WE or 3.33 monsters per WE. It has 1/ 1.5 loot rolls per WE.

Stage 2.6-9N with 1200 iron per WE, 2.5 recruits per WE, and I can auto play with the Wu Kong grinder gang ( see links below ). This has 11 to 17 monsters for 6 WE or 2.33 monsters per WE. It has 1/ 1.5 loot rolls per WE.

What are your favorite levels to iron farm?


Click for notes

Examples of iron farming

From Barry’s helpful data project
( Barry Farmz Here -- Comprehensive data driven farming guide )

1.17-1 = 1510 ( 1.4 recruits)
1.7-7= 1017 ( Rugged clothes)
2.15-9N= 1193 ( 2.857 recruits)

2.6-9N= 1200 ( 2.5 recruits)
1.12-9= 1388 ( 2.5 recruits)

1.9-1= 1350 ( 2.0 recruits)

Loot rolls


Wu Kong grinder gang
(Wu Kong grinder gang or Powerful rainbow auto play team or Wu Kong plus 4 healers)


Raid nerf

Click for raid nerf

First link caused all food and iron gains to decrease because of the way Elo’s math works. This is especially true if you do not trophy drop.

The second link increased drops for 3*/ 4* ascension items, Epic tokens and Trainer heroes, but nerfed food/ iron from raiding.

Both made the watchtower much more useful, but raid energy flasks much less useful.



I’m just in awe of how far through the lodge you are already!

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Strange enough, I still have iron maxing out every 4 days or so…you have developed your base more than I have . I’ve been bled dry of iron and food crafting the new buildings and items, but once I don’t create battle items iron replenishes so I haven’t had to start farming Iron ( yet).

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That’s exactly why i’m using my second builder on mine and iron storage.

Originally too i was planning to upgrade the house to get more recruits, but i don’t have any particular need for more of them right now so i just keep the level 1.

I did not even convert the hunter lodge.
I couldn’t care less of harpoons, and don’t want to use more irons on them.


I made harpoons a priority. I am also leaving the hunters lodge at level 1. I’ll build up Titan parts so I have a nice stockpile when I finally decide to raise the lodge.

I have been raising the advanced mine (costs food) and the advanced iron storage (costs iron) with my 2 builders. When those are max, I’ll start doing the advanced farm.

I want my iron storage at max so I will be ready when more stronghold levels become available.


I wish I had done this (or not done it!). Harpoons eat up iron, and most of my alliance has no idea what to do with them anyway — it’s just a waste of resources right now, and I sure could have used that iron I used on the lodge to upgrade the mine or storage. Ditto with the house — I now have more recruits than I can use!

Same here. I am only making harpoons when my iron is in danger of hitting the storage cap.

I am currently working on advanced mine and house, though I may switch to iron storage sooner, rather than later.

I am not actively farming for iron. When I was shorthanded early on, I just raided for it (and learned the limitations of that approach). :slight_smile:

I am finding myself iron limited and unable to craft all the battle items I want, use all the emblems I have, and keep both builders active 100% of the time now. That said I’d put some perspective on farming for iron as a top priority

Best Iron farming is S1:17-1 at 1510 Iron/WE = 217k Iron/day
Crappy Iron farming, S1:5-8 is 717 Iron/WE = 103k Iron/day.

That most extreme difference is 115k Iron/day using 144 daily flags. Other good farming levels with intermediate iron end up with 18k to 46k less iron per farming day.

One level 20 mine = 89k Iron/day, 5 of them is 434k Iron/day.

Between iron I win on raids, iron I get in raid and monster chests, iron I get in titan loot, I figure I get at least 200k iron per day. (Rough but conservative guess, and yours may vary significantly from mine)

Adding it up, out of a total of ~851k iron/day coming in at the best farming levels for iron, I lose between 115k and 18k farming elsewhere–At most 14% down to as little as 2% of my daily iron income, depending on how “bad” the iron return I’d get at my other choice of levels to farm.


Yep, focusing on getting the advanced house to lvl 9, while my alliance figures out what harpoons are and how to use them. Someone fired one (!) at the titan two days ago, nothing since. That tells me I’ve made the right decision.

Well, you should start upgrading the iron storage too. When the stronghold lvl 22 will come out, you will need the advanced iron storage at lvl 5. For stronghold lvl 23, at lvl 10. And you should complete heroes chests more often, for that amount of iron. Good luck!

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I understand wanting to make iron production quicker, but I am about to go from level 4 advanced mine to level 5. The cost in iron to do so is 1047k with an increase of 150 iron/hour. It will take 3d14h to complete the upgrade. All that time the mine will not be producing iron. I currently produces 3074/hour. That is an initial 1,311,364 loss of iron to upgrade to level 5. It will take 8742 hours (365 days). (1311364/150=8742/24=~365) It will take a complete year to make up for the iron lost to upgrade from level 4 to level 5. Not to mention the amount from level 20 basic to level 4 advanced.
Why am I upgrading my iron mine? I am forced to upgrade the iron storage to complete the bigger buildings, but this is not cost effective.

Oops. I just realized it costs food to upgrade iron mines. This post is useless.


Even if I am using food to upgrade. It will still take 84 hours to upgrade. 342216 lost production of iron during construction. With a increased production of 150/hr it will take 2281(95 days) hours to recoup the cost of upgrade. I did not calculate this on the previous 4 upgrades because I was just so excited to be able to increase my iron production. Now I am pretty sure why I have only one builder working and am so desperately short of iron I did the mine iron quest.


Massive waste of resources for micro returns. Like the queen I’m not amused…

I’ll spend my iron to craft storms while waiting for some input, if lab and academy will be as disappointing as the mini advantages from the advanced buildings.

The lodge also not makes me feel like if it’s worth. Items will consume masses of food and iron and you need masses of iron to craft harpoons for titan parts, too.

I need vacancy for my 2nd builder.

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You made me smile.

I’ve done this many a time where I burst into a fit of passion…

… only to realise that my foundational assumption was completely wrong lol

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^^ QFT

I have one VIP builder doing nothing but Advanced Iron Storage for this very reason.

The other VIP builder is doing primarily Advanced Food Storage, which will be necessary for Alchemy Lab Research. When the timing of this builder would impact necessary Iron for builder #1 then they work on Advanced Mine using Hams instead.

I got my Advanced House to Lvl 3, which seems to be a sweet spot of return on investment at this point. Hunter’s Lodge got cranked up to Lvl 3 before I figured out I should be working on the Storages first.

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Here’s the thing that offsets that… with the strategy outlined in my previous post [and assuming 2 VIP builders] you quickly get to a point where the build times become drastically long on the Storages. This means you can afford to have one builder work on an Advanced Mine and sacrifice the Iron it would produce because the other three Lvl 20 Mines (along with farming & Raiding, etc.) produce enough to recover over the build period to kick off the next building when the first builder finishes.

I get Advance Iron Storage Lvl 8 finished tonight. Advance Mine is sitting at Lvl 8. Advance Food Storage is cranking through Lvl 6 right now. Since the release of SH21 I’ve been running two builders essentially non-stop with only a few hours of idle time at the very beginning.

Stronghold 22

Luckily a second Advanced Iron Storage now unlocks at Stronghold 22 ( previously Stronghold 23 )

(🧪 The Beta Beat (v23) – Sharing the Big Picture on What's Going on in Beta: Stronghold 22/23 & Alchemy Lab, New Challenge Event Heroes, New Knights of Avalon Event, Costumes)

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Advanced Iron Storage 10

That was my original plan. You previously needed Advanced Iron Storage Level 10 for Stronghold 23.

Hobbled Stronghold

Since Stronghold only goes to 21,
There is no way to hoard iron,
I prefer to waste zero iron,
I have been forced to change my plans.

I had intended to take Advanced Iron storage to 10, but with 3x Iron Storage Level 20 and 1x Advanced Iron Storage Level 8, I only have a 92k buffet between the 2325k I need for Advanced Iron Storage 9 and the 2417k maximum storage I have. 92k is less than I can get from the 8 chests.

I am stopping at 1x Advanced Iron Storage Level 8, until I have 2x Advanced Iron Storage Level 8.

Current buildings

Advanced Mine 10 ( done )
Advanced House 3 ( target 9 )
Lodge 1
Advanced Iron storage 8
Training Camp “Delta” 17 ( target 20. For Cyprian.)

Next construction

Advanced House 9
Training Camp “Delta” 20
Advanced Farm 10
Advanced Food storage 6

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I do find it rather a pain in the neck to manage something that requires iron within a few k of maximum iron.

So I’m quite happy my adv iron storage will be at 10 in 20 hours … and my advice food storage will hit 9 in another 4 days. Plus increasing storage capacity will give me more iron and ham in at least raid chests if not other chests.

I’ve already got my 1st adv farm maxed and my hunter’s lodge to 2 … I think the titanium shield at 3 will be a priority for me before I see a 13* rare titan.

As soon as I can I’ll be doing SH22 and all the 10s conversions it unlocks.

Since I’m still in ham shortage permanently, at that point, one builder will be maxing my second adv farm.

Dunno what I plan to focus on with the other builder and when the farm is done yet. Maybe SH23 and the alchemy lab; if I decide I can afford the resources to run it it will take a long time to convert surplus mats/etc. so I’ll want to get started sooner instead of later … but I suspect I’ll be putting my hams toward feeding troops and heroes instead … in which case I’ll focus my iron on storages and the adv house and hunter’s lodge instead…and being ready to decide if the hero academy will be worth it for me or not.

I do know I’m still prioritizing ham over iron so my adv mines aren’t gonna get past level 1 until I’m out of heroes and troops to feed with hams!

Farms and mines take Alot of resources and time to upgrade for very little increase in production

Ditto for iron and food storages

New items and buildings take excessive amounts of resources to craft

It seems like the resource and time cost are very high just for the sake of being high, to give players something to do

I feel like the mouse running on the wheel, forever running but never getting anywhere


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