Explanation:
the guideline in this question is wrong.
9½ teaspoons is 9 teaspoons and ½ teaspoon.
or if it was meant 9×½ = 9/2 teaspoons, then this is 4 teaspoons and ½ teaspoon.
the point 5 is not described completely. I am going to ignore it.
the recipe is for 16 portions (times) of 8 fl oz (240 ml).
when we need only 4 portions of 8 fl oz, the scaling factor for ALL ingredients is then 4/16 = 1/4.
that means we need to multiply every quantity in the recipe by 1/4 (divide by 4).
2 LB chicken pieces -> 2/4 = 1/2 LB
8 oz diced carrots -> 8/4 = 2 oz
1 LB diced onions -> 1/4 LB
8 oz diced celery -> 8/4 = 2 oz
8 oz parsnips -> 8/4 = 2 oz
128 fl oz water or chicken stock -> 128/4 = 32 fl oz
2 bay leaves each serving = 2×4 = 8 bay leaves
2 tsp dried Thyme leaves -> 2/4 = 1/2 tsp
1 tsp black peppercorn -> 1/4 tsp
the salt/white pepper guideline has not changed.
when we need 100 portions of 8 fl oz, the scaling factor for ALL ingredients is then 100/16 = 25/4 = 6¼.
that means we need to multiply every quantity in the recipe by 25/4 (or 6¼).
2 LB chicken pieces -> 2×25/4 = 25/2 = 12 LB and ½ LB
8 oz diced carrots -> 8×25/4 = 2×25 = 50 oz
1 LB diced onions -> 1×25/4 = 25/4 = 6 LB and ¼ LB
8 oz diced celery -> 8×25/4 = 2×25 = 50 oz
8 oz parsnips -> 8×25/4 = 2×25 = 50 oz
128 fl oz water or chicken stock -> 128×25/4 =
= 32×25 = 800 fl oz
2 bay leaves each serving = 2×100 = 200 bay leaves
2 tsp dried Thyme leaves -> 2×25/4 = 25/2 =
= 12 tsp and ½ tsp
1 tsp black peppercorn -> 1×25/4 = 25/4 =
= 6 tsp and ¼ tsp
the salt/white pepper guideline has not changed.