Which is worse? Heat or cold?

[SteveR]

Hi, I started brewing a few months ago and have enjoyed every batch I've made so far. (About 10) I have been keeping my fermenters in a closet during the cooler months and the temperature has remained fairly contant; between 68 and 72 degrees. (I'm only brewing ales)

Now the Northern California summer heat is beginning. This week daytime temps here in Marin are reaching nearly 90. My closet gets up to 80+ degrees. I have no air conditioning.

So I have been keeping my carboy and primary buckets in my crawlspace under the house. This seems better, as the temp only reaches about 75, max. However, at night time the temperature in there can drop to about 60 degrees.

So what are my options? Which is worse...the colder temps or the higher temps? I really don't fancy lugging a carboy back and forth into the house twice a day. Additionally, how important is the typical "65 - 75 degree" range? Will temperature fluctuations affect the flavor only, or can it completely ruin a batch?

THANKS SO MUCH!
Steve

[Redbird Fan]

yes, temperature fluctuation can effect the taste of your brew - in fact some brews require temp fluctuation to achieve the desired taste (lagers).

I feel high temp is much more detrimental than cooler - too high a temp will cook your yeast (kill them) - cooler temps will cause them to go dormant, in which case fermentation will be too slow and/or not at all, but you can "revive the yeast" (bring them back to active) by raising the temp.

It sounds like your situation will be difficult, but could most easily be resolved with a little cash - you may want to look into researching how to build a cooling cabinet with an old refrigerator.

The good news is, there will likely be many other suggestions on how to solve this problem, I'm just not well versed in keeping a constant cool temp in a high temp situation.

[batkins]

In a 10-15 degree environmental fluctuation, is the temp of a 5 gallon batch of beer really going to vary that much? I would think that the overall temp would stay pretty steady.

[Tweek]

I had a similar situation in my last place. What you can do is go ahead and get a decent blanket and wrap it up under your crawlspace. that will keep it insulated enough that you dont loose or gain too much in that minor of a temperature shift.

By the way we are neighbors. I over in SF. You should sign up for the community brew and then we could exchange in person.

Cheers

[Redbird Fan]

you may have a point with the 10-15 degree overall temp fluctuation having little impact on the beer (although I feel it will - time is going to play a factor in this fluctuation), but the temperature of the brew he's describing seems too high. I believe a fermentation temp above 75 F will present him with off flavors (if not kill his yeast all-together).

[b3s]

i would not worry about a 10-15 degree air temp change too much...not enough time for water to change temp, let alone a heavy liquid like, say, beer. keeping it in a crawl space i would be more inclined to worry about pests (you know...neighbors, brothers-in-law, etc.).

in the end i'd have to say, to answer the question in the topic line, yes...either, in excess quantity, would be bad...at some point the temp can get low enough or high enough to kill yeast...but since we're talking about a mild maritime climate, i'd be more inclined to worry about heat...well, except for the fact that mark twain once wrote that the coldest winter he ever spent was a july in san francisco....

[SteveR]

Wow...them's some quick resposes! I never thought about the actual temerature fluctuations of the beer itself. I've just been setting a thermometer next to the bucket. I am going to try wrapping it with a blanket too. I think the crawlspace is the way to go. Now if I could just move my couch and tv down there...

Tweak: yeah, you've got natural air-conditioning in SF. Pretty much perfect brewing temp all year long. I moved to Marin two years ago after living 12 in the City. The main reason for the move was because I couldn't take the cold and fog any longer! I needed sunlight! But that was before I began brewing. Hmm. Maybe we can trade some beers indeed!

Steve

[brewmonkey]

Extreme temps like you mention can and will effect your product. One side effect could be (if IIRC) production of fusel oils (higher alcohols) as well as some esters that will prove to be unpleasent and unable to be conditioned out. The esters would give a very vinous almost laquer or paint thinner aroma and possibly flavor to the beer.

Depending on the strain of yeast involved you could also have higher production levels of diacetyl and or DMS (depending on the malt used). In the case of diacetyl it is possible that the level is well above threshold and unable to be reduced during conditioning due to yeast mutations/deterioration leaving you with a very buttery beer. Repitching a new culture may help, but I doubt it.

Several methods that could work for you are buy a small tub from wally world (walmart), place the carboy in it and then fill with water about 1/2 way. Place an old shirt over the carboy so that the bottom rests in about2 inches of the water. This will act like a wick and sweat some of the heat away. Refill as needed till fermentation is complete. If need be add some ice at intervals to help the temp stay in the range.

If it is dificult to keep temps below about 70F brew your Belgians in the summer (as I do). The yeast likes the higher fermentation temps.

[YamahaXS]

my 2 cents:

Heat transfer is facilitated by 2 things: humidity and wind. Your closet is probably an easier place to control these things.


In either case, wrap your carboy in an insulating material, for crawlspace insulate from the ground too. This will minimize heat transfer and your wort/beer will not fluctuate too much in either location (assuming the average temp is within a good range AND you can adequaltely insulate.

[BluesHarp]

I would worry about heat more. I had an experience where I had brew fermenting during an extended 90° plus heat wave; the ber (pale ale) definately had some odd flavors, still drinkable, but not at all what I wanted. Cold will slow the yeast, but they will wake up when they warm up again. I've never had a bad batch due to low temps; just takes longer.

[Daren]

Originally posted by b3s
i would not worry about a 10-15 degree air temp change too much...not enough time for water to change temp, let alone a heavy liquid like, say, beer.

You wouldn't think it would change much, but I know from experience that it will. During the winter time, the temperature fluctuates between 68-70 F in the day and 56-60 F at night in my house. I do see swings of 6-10 degrees in the temperature of the beer in my fermenter. The temperature changes of the beer in the fermenter just lag behind the ambient temperature changes. To correct my problem I just put a heat belt on the fermenter at night and take it off in the morning. That may be an option with the crawl space too. Good luck.