Odd lager fermentation

[beernutz]

I say odd but I don't really know as the vast majority of beers I've brewed have been ales. Anyway I brewed a 10 gallon batch of a Heineken clone on 8/10 using
1 lb crystal 15L
1 lb caramunich
20 lbs pilsner 2 row
2 oz saaz 10 min
4 oz saaz 60 min
WLP 800 pilsner lager yeast in 4l starter

Brew day was uneventful and I put both buckets in my freezer fermentation chamber at 50. SG after the boil was 1.052 and about 72 % efficiency as I ended up with just over 11 gallons I think.

On 8/19 (9 days in fermenter) I tested SG and it was 1.038. I raised the temp up to 53 degrees and moved the buckets around a bit.

On 8/23 (13 days in fermenter) I again tested SG and it was down to 1.028. I didn't adjust the temp at all nor did I agitate the buckets.

I was trying to follow the suggestion I've read here and elsewhere to do a diacetyl rest when fermentation was about 75% complete. Based on a starting SG of 1.052 and estimated ending SG of 1.012 I figured that would be around 1.022.

Things got busy and only today 8/29 (19 days in fermenter) did I get around to retesting SG and it was down to 1.010 at 60 degrees! I immediately set the freezer temp controller to 65.

I've tasted my samples used for gravity testing each time and couldn't detect any butter or butterscotch and in fact they tasted fine. However I've read that the precursors to diacetyl could still be in there lurking about, waiting to come out and screw with my beer.

I suppose I need to ask a question at this point so is there any thing else I can do to ensure that diacetyl is minimized at this point? Also, after I set the temp controller to 65, presumeably it takes many hours for the actual beer temp to rise to that level. How long should I leave it set to 65? I was planning to rack straight from the primary buckets into kegs once the rest was finished prior to lagering.

Thanks and sorry for the long post.

 

[LLBeanJ]

Depending on your temps at pitching (both wort and the yeast), you may not need the rest, but there's no harm in doing it anyway. Give it a few days at 65 and you should be good to go.

 

[beernutz]

Depending on your temps at pitching (both wort and the yeast), you may not need the rest, but there's no harm in doing it anyway. Give it a few days at 65 and you should be good to go.

Yes, I forgot to add that information. My CFC got the wort down into the low 70s, 72 I think, so I put the buckets in my freezer set to 50 and left them a couple of hours and then pitched. I'm not sure what the temp was at that point as I neglected to take a reading.

I probably could have/should have waited until the next morning to pitch. I also could have set the temp to lower than 50, pitched when the wort had reached that temp, then let it rise back up in to the low 50s. Like I said, I don't do many lagers and I was paranoid about waiting too long to pitch as I always immediately pitch when brewing ales. Live and learn.

The yeast starter was taken right off the stir plate at room temp which I'd estimate was 76. Thanks for the reassurance.

 

[LLBeanJ]

Right on. Given the difference in temps between the yeast and the wort at pitching, I'd definitely go with the D-rest to be on the safe side.

 

[beernutz]

Right on. Given the difference in temps between the yeast and the wort at pitching, I'd definitely go with the D-rest to be on the safe side.

Thanks again.