I brewed my first AG, now I have some questions

After brewing two extract brews with good results I thought I would go all in and give AG a try. I also thought I would try to do an AG version of the last batch I brewed and pour it on the leftover yeast cake.

So here is what I started with:

12 lbs Pilsner Malt
.5 lbs Caramunich Malt 40L (or maybe it was 60)
.5 lbs Crystal 120L
2 lbs Belgian Candi Amber

For the boil:
.65 lbs Green Raisins, chopped, and boiled wort down to 4 gal to leave room for aeration in 5 gal pot

.75 oz Simcoe 60 min
1 oz Licorice root 60 min
.5 oz Simcoe 30 min
.25 oz Simcoe 15 min
Irish Moss and Yeast Nutrient 15 min
.25 oz Simcoe 5 min
Sour Orange zest 5 min
6 g Indian Coriander 5 min
2 g Grains of Paradise 5 min
.25 oz Simcoe 1 min

I cooled the 4 gal of wort and aerated it. Then strained it onto the leftover yeast cake, and topped it off with water to get 5gal in the carboy.

My question is how should I get my OG? The wort that went into the carboy was 1.121 @ 75F and the liquid in the carboy with the yeast and top off water was 1.088. What should I use as an estimate for this brew?

Oh and the previous batch was fermented with Wyeast 1388 Belgian Strong. Thanks in advance.

Mix it all up and check the OG? I don't know how else to do it, except to do the math.

4 gallons of 1.123 wort, plus whatever you had in the carboy.

I could figure it out, but I don't know what made the wort 1.088 if it was water and yeast.

Not be a negative Nancy, but I would generally avoid pitching Belgians onto a cake unless the beer in question is really HUGE or you decant off some of the yeast first. You almost surely over-pitched which normally isn't a huge problem for a lot of cleaner tasting beers, but w/ a Belgian you could possibly be missing out on that distinct estery profile that makes it a Belgian in the first place.

I found this quote in another thread from Dave Logsdon of Wyeast:

“I try to stay within 20% of my ideal pitch rate and I prefer to slightly under pitch rather than over pitch. This causes more cell growth, more esters, and better yeast health. Over pitching causes other problems with beer flavor, such as a lack of esters. Changes in the flavor profile are noticeable when the pitch rates are as little as 20% over the recommended amount.”

Click to expand...

Now w/ that being said you'll probably still end up w/ awesome tasting beer. Just something to think about in the future.

I dunno I pitched a tripel on a wyeast 1214 yeast cake left over from a wit and it turned out fantastic. Plenty of esters. It is also the fastest I've ever seen 1214 produce an active fermentation.

Yeah, with an OG of over 1.100, I don't think overpitching is an issue.