In the last SGOTM, Dhoomstriker and I ran some extensive testing to find the best time to whip a granary. Dhoomstriker had read an article stating that the food that overflows when you grow in pop after building the granary also counts as being put into the granary storage. Let me explain with an example, which was done at Epic speed.
Assume that we start with a city at size 2.
Test 1:
T0 - 12/36 - whip granary - 12/33 +5F/turn
T1 - 17/33 - +5F
T2 - 22/33 - +5F
T3 - 27/33 - +5F
T4 - 32/33 - +7F (I worked a higher yield food tile to maximize the overflow)
T5 - Grow to 2
On the turn I got the granary (T1), I had 17 food. 33 - 17 = 16. Perfect. The granary should have 16 food in it when I grow from 1 to 2, right? Wrong!! On T4 I had 6 food overflow (32 + 7 = 39; 39/33 leads to 6 food overflow). So, on T5 my granary actually had 16 (max granary storage) + 6 (overflow food) = 22 food, not the expected 16 food. That 6 food overflow on T4 actually got added to the granary storage. Nice!!
Test 2:
T0 - 16/36 - whip granary 16/33 - +7F
T1 - 23/33 - +7F
T2 - 30/33 - +7F
T3 - Grow to 2
Conventional wisdom states that since I completed the granary on T1, the granary would only have 10 food in storage (33 - 23 = 10) when we grow on T3. However, the overflow on T2 also gets put into the granary storage. So, the granary actually has 7 (food from T1) + 7 (food from turn 2) + 4 (overflow from T2: 37/33 leads to 4 overflow) = 18!! It appears that the expected 10 food in the granary storage actually grew to 18 food.
So, how much food do we want in Moscows granary when its completed?
I ran a quick test and this is what I found:
T90 - 3/30 - 66/100 in settler - +31 hammers
T91 - 3/30 - 97/100 in settler - +31 hammers
T92 - 3/30 - 0/60 in worker - +44 hammers (14 overflow)
T93 - 3/30 - 44/60 in worker - +23 hammers
T94 - 3/30 - 0/60 in granary - +24 hammers (4 overflow) +6 food (Moscow moves from gold to rice; Fish works the gold)
T95 - 9/30 - 24/60 in granary - +18 hammers - +6 food
T96 - 15/30 - 42/60 in granary - +18 hammers - +6 food
T97 - 21/30 - granary done - +6 food
T98 - 27/30 - +6 food
T99 - grow to 6 pops - 15/32 (6 from T97 + 6 from T98 + 3 overflow from T98 = 15 food).
So we get the expected 15 food in the food basket even though we actually completed the granary with 21/30 food. Conventional wisdom says that we would have only had 9/32. Not true!
What happens if we slow grow Moscow for a turn as suggested?
T96 - 15/30 - 42/60 in granary - +22 hammers - +1 food (work gold rather than rice)
T97 - 16/30 - granary done - +6 food (switch back to the rice)
T98 - 22/30 - +6 food
T99 - 28/30 - +6 food
T100 - grow to 6 pops - 19/32 (6 from T97 + 6 from T98 + 6 from T99 = 18 (cap is 30/2 = 15 + 4 overflow from T99 = 19 food).
OK, by slow growing we arent necessarily better off because we grow to 6 pops one turn later and only have 19/32 food. In the first example, we would have 15 + 4 = 19/32 on T100 as well. The extra turn on the gold mine on T96 is made up by growing a turn sooner and working the gold on T99. In this case, we could go either way depending on if/when Fish can work the gold. Also, in the case of slow growing by working the gold, we actually end up losing 3 food due to the granary storage capping at 15 turning our possible 18 food into 15.
However, what happens if we try this:
follow first example until
T98 - 27/30 - +8 food - switch from the horses to the farm (trading 1f/4h/1c for 3f) !?
T99 - grow to 6 pops - 19/32 (6 from T97 + 8 from T98 + 5 overflow from T98 = 19 food).
So, by working the farm rather than the horses for a turn, we arent trading 4h/1c for 2f as it appears at first glance. Due to the overflow food in the granary, we are actually trading 4h/1c for 4f!! (15/32 in the basket vs. 19/32). Is 4f > 4h/1c? I think so