Seq.concat wasn't working right (was only checking the recipe queue). Async wasn't working either but this seems to do ok.

gistfile1.txt

module Program

#light

open System.Threading
open StructureMap
open BrewTelligence.Domain
open BrewTelligence.Search.Indexing
open BrewTelligence.ApplicationServices
open BrewTelligence.ApplicationServices.Messaging

ObjectFactory.Initialize(fun x -> x.AddRegistry (new SearchRegistry()))

let write<'T when 'T:null and 'T:equality> item =
    if not (item = null) then
        ObjectFactory.GetAllInstances<Indexer<'T>>()
            |> Seq.iter (fun idxr -> idxr.Index item)

let itemsToIndex<'T when 'T:null and 'T:not struct> =
    let p = QueueProvider<'T>.Create()
    seq {
        while true do
            yield p.Dequeue()
    }

try
    itemsToIndex<Recipe>
    |> Seq.zip itemsToIndex<Malt>
    |> Seq.zip itemsToIndex<Hop>
    |> Seq.zip itemsToIndex<Addition>
    |> Seq.zip itemsToIndex<Yeast> 
    |> Seq.iter (fun (recipe, (malt, (hop, (addition, yeast)))) ->
            write recipe
            write malt
            write hop
            write addition
            write yeast)

finally
    SearchRegistry.DeRegister()