Both times after several generations with LDM I tipped most of the malt mix off after activity had stopped swirled the small amount of remaining LDM mixand then pitched the yeast. After a bit of reading on this site it seems people are pitching this yeast when it is still active.
So, is it best to pitch this yeast when it's dormant like I have previously or when it's active? I am going to make another ESVA tomorrow cause it's so bloody good.
There are advantages to both approaches, it really depends on your starter wort, beer wort and procedures.
The advantage is that when you pitch the starter at 'high krasuen' the yeast is active and presumably very healthy, however it also means pitching the full volume of the starter (which might be oxidized or have other off-flavours) into your beer, this is something that many people (myself included) hesitate to do.
On the other hand, if you let the yeast settle out, you can pitch only the yeast and will have no off-flavours from the starter/proccess introduced to your beer.
I always tip the whole starter in once krausen has been reached, by tipping all the wort from the top ofthe starter you are getting rid of alot if healthy yeast that are in suspension.. And by tipping just the settled layer on the bottom you will be pitching sluggish or unhealthy yeast that might floc out early and give a stalled ferment...
While pitching the yeast at 'high krasuen' does ensure that the yeast is active and healthy, it's not always the best approach in terms of yeast/fermentation health.
Active yeast 'condition' themselves for the specific wort they are growing in (types of sugars etc), if they are pitched into 'different' wort they may not be well prepared for the change in wort/environment and that is not always good for the yeast.
On the other hand, because starters involve a large amount of yeast in a small volume of wort, they should ferment out very quickly (which should only take ~24h or so more than pitching at 'high krasuen'). But if you do let the starter fully ferment and then settle, this allows the yeast to build up their food reserves (glycogen, trehalose) so that the yeast have a ready food supply to help them adapt to the new conditions when they are pitched into your beer. If - once the starter has fully fermented and settled out - the yeast is not stored for an extended period of time (more than a week or so), it's not going to be 'more unhealthy' than yeast pitched at 'high krasuen' and in some situations it might even be argued that it's actually 'more healthy' due to the build up of food reserves.
When stepping up starters I'll pitch them after 'only' 24 hours (which is usually when the yeast is active but after the majority of yeast-cell growth has occurred), since each starter step uses the same wort and we're looking to grow yeast not ferment beer. However at the last step, I usually allow a day or few extra, to let the yeast ferment the starter fully and then all settle out (it can be put in the fridge to help the yeast flocculate if required) before decanting the spent starter beer and pitching only the yeast (if there is any yeast left in suspension at that stage it will only be the least flocculant yeast and so I don't mind the possibility of tipping it, since discarding that yeast might help clear my beer quicker after it's finished fermenting).
