White Labs, slow start or no start?

Hi, I just brewed a recipe for a Belgian Dark Strong Ale. I have brewed this in the past and really like the way it turns out. The yeast I used was White Labs wlp 500 Trappist Ale. Anyway i pitched the yeast almost 24 hours ago and i am seeing no signs of fermentation. How long should I wait before i repitch? Also I happen to have a few packets of safbrew-t58 on hand. will that yeast give a similar flavor profile as the trappist yeast?

Needs more info.

Did you use a starter? If so, how big?
Did you oxygenate or aerate your wort? If so, which, and for how long?
What temperature are you fermenting at?
What was the expiration date on your WL vial?

What was the OG of your wort?

It is too soon to even begin to worry....after 72 hours is when you take a gravity reading and see what's going on. It's quite common for yeast to take 2-3 days to get going, it's called lag time.

https://www.homebrewtalk.com/f39/fermentation-can-take-24-72-hrs-show-visible-signs-43635/, and by visible signs we don't necessarily mean a bubbling airlock. it means gravity reading

It IS a sticky at the top of the beginners forum for a reason, afterall.

"Activity is irrevelent." Just gravity points on a hydrometer.
Airlock bubbling (or lack) and fermentation are not the same thing. You have to separate that from your mindset. Airlock bubbling can be a sign of fermentation, but not a good one, because the airlock will often blip or not blip for various other reasons...so it is a tenuous connection at best.

Fermentation is not always "dynamic," just because you don't SEE anything happening, doesn't mean that any-thing's wrong,, and also doesn't mean that the yeast are still not working diligently away, doing what they've been doing for over 4,000 years.

The most important tool you can use is a hydrometer. It's the only way you will truly know when your beer is ready...airlock bubbles and other things are faulty.

I did not use a starter. Its a 10 gallon recipe and i used 2 vials of yeast. i do aerate for about 5 minutes. it is fermenting at around 65 degrees. the yeast expires in july of this year.

oh and the original gravity was 1.071@73 degrees

I always make a starter for White Labs vials, and they rec a starter for any beer over 1.060.

http://www.whitelabs.com/beer/homebrew_FAQ.html#starter

Lag time is laggy. Hurry up and wait, or pitch more.

Yeah, 10 gallons at 1.071, you underpitched by quite a bit with only 2 vials. Not going to be a show-stopper by any means - you MAY notice some off flavors and, as you're seeing now, you WILL notice a longer lag time than you would see with a dry yeast (dry yeast packets typically have far larger cell counts in them than do liquid yeast vials or smack packs).

Try using the Yeast Pitching calculator at MrMalty.com to better calculate yeast pitching rates. According to that, your beer should have ideally had either 5 vials pitched, or those same 2 vials pitched into a 6.27 liter simple starter.

Again - underpitching will NOT lead to a ruined batch, by any stretch. But it will lead to a batch that will be slower to take off, which does provide a slightly increased chance for other things (bacteria, wild yeast, and the like) to take off in your wort if your sanitation wasn't good, but it can also sometimes lead to some off flavors generated during that lag time...

considering how much you under-pitched, i'd be tempted to through in a rehydrated T-58 to provide some backup to the White Labs. there is enough sugar in the wort for both yeasts.

T-58, while not identical to 500, is in the same ballpark. it'll make a great beer.

The last two of my brews have been White Labs. I used a starter on both of them.

They are fantastic!!! Both had high krausen in the flask, in fact the WLP400 Belgian Wit I just used overflowed the Erlenmeyer flask. I pitched it, and had active airlock activity in 6 hours. That was Saturday.

Today, I just got home from work, and the airlock is all clogged up, and I use Ale pales.

I love this stuff.