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Temperature control and summer brewing

Controllers, chambers, heat wraps, glycol, insulated bags and kveik yeast for garages that run hot in summer and cold in winter.

Fermenters & temp control 18Hydrometers & meters 3Yeast & nutrients 8Wine, cider, mead & kombucha 1
The empty white interior of a refrigerator, the start of a fermentation chamber
Photo: Satirdan kahraman, CC BY-SA 4.0, via Wikimedia Commons

How to control fermentation temperature in summer

Fermentation temperature control matters most when the garage runs hot. Yeast makes its own heat during active fermentation, so a fermenter can sit several degrees above the room, past the range on the packet. You have three ways out: cool the beer (a chamber, glycol or an ice bath), insulate it, or choose a yeast that likes heat.

FixWhat you needBest for
Fridge or freezer chamberDual-stage controller + heat wrap✓ Any style, all year
Glycol chillerChiller, coil or jacketed fermenter~ Conicals and multiple fermenters
Insulated bag or swamp coolerBag or tub, frozen bottles~ Ales in a mild garage
Kveik or saison yeastA heat-loving strain✓ Hot garages without power

Fermenters & temp control

All 18 in fermenters & temp control

Hydrometers & meters

All 3 in hydrometers & meters

Yeast & nutrients

All 8 in yeast & nutrients

Wine, cider, mead & kombucha

All 1 in wine, cider, mead & kombucha

Yeast that tolerates the heat

Kveik strains ferment clean at temperatures that would make a normal ale taste hot. LalBrew Voss lists 95–104°F (35–40°C) as optimal; Omega Lutra lists 68–95°F (20–35°C). Saison strains like Fermentis BE-134 (64–82°F) also suit summer.

Dry yeast by the maker’s numbers

YeastUseFermentation tempDoseAttenuation / toleranceRehydration
SafAle US-05
Fermentis		Ale (American)18–26°C (64.4–78.8°F)50–80 g/hL78–82%; not listed on the product pageOptional: ≥10× its weight of sterile water or boiled, hopped wort at 25–29°C (77–84°F), 15–30 min; or direct pitch at or above fermentation temperature
SafAle S-04
Fermentis		Ale (English)18–26°C (64.4–78.8°F)50–80 g/hL74–82%; 9–11% ABVOptional: ≥10× its weight of sterile water or boiled, hopped wort at 25–29°C (77–84°F), 15–30 min; or direct pitch at or above fermentation temperature
SafLager W-34/70
Fermentis		Lager12–18°C (53.6–64.4°F)80–120 g/hL80–84%; 9–11% ABVOptional: ≥10× its weight of sterile water or boiled, hopped wort at 15–25°C (59–77°F), 15–30 min; or direct pitch at or above fermentation temperature
LalBrew Nottingham
Lallemand		Ale (English)10–25°C (50–77°F)50–100 g/hL78–84%; 14% ABVDry pitching is the maker's preferred method (no significant difference vs rehydration, per Lallemand)
LalBrew Voss (kveik)
Lallemand		Ale (kveik)25–40°C (77–104°F)
Optimum 35–40°C (95–104°F) per Lallemand		50–100 g/hL76–82%; 12% ABVPer the sachet
Lalvin EC-1118
Lallemand		Wine, cider, mead10–30°C (50–86°F)25 g/hLFerments dry; 18% v/v (subject to conditions)35–40°C (95–104°F) water for 20 min with Go-Ferm Protect Evolution (30 g/hL), then temper to within 5–10°C of the must

Sources: Fermentis: SafAle US-05 product page; Fermentis: SafAle S-04 product page; Fermentis: SafLager W-34/70 product page; Lallemand: LalBrew Nottingham technical data sheet; Lallemand Brewing: LalBrew Voss Kveik Ale Yeast product page; Lallemand: Lalvin EC-1118 technical data sheet. 1 hL = 26.4 US gal, so 50 g/hL ≈ 1.9 g per gallon. Follow the sachet you buy; makers update their sheets.

Chamber setup and winter heat

Plug the fridge into the controller's cooling outlet and a heat wrap into its heating outlet, then tape the probe to the fermenter under insulation. Use the compressor delay to protect the fridge. The same setup warms a cold winter garage for ales, or holds 48–55°F (9–13°C) for lagers.

Water tubs, wet towels and power cords share the floor in a swamp-cooler setup, so plug everything into a GFCI-protected outlet.

Electric brewing: GFCI and a licensed electricianPlug 120V and 240V systems only into a GFCI-protected circuit of the type the manual calls for, with no extension cords. A 1600 W system on 120V draws about 13.3 A (W ÷ V), close to a 15 A circuit’s limit. Have a licensed electrician install any new circuit, 120V or 240V.Source: Anvil Foundry manual (GFCI protection for 240V hookups); W ÷ V arithmetic

Who should choose what

  • Hot garage, no spare fridge: kveik or saison yeast, plus an insulated bag.
  • Spare fridge or chest freezer: a dual-stage controller and a heat wrap, for any style all year.
  • Several fermenters or a conical: a glycol chiller.
  • Kegerator owner: use it as a fermentation chamber between batches.

Check the seasonal calendar for what suits each month in a hot-summer or cold-winter garage.

Related reading: best dry yeast for IPA and pale ale.

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Temperature control & summer: questions

What temperature should beer ferment at?
Follow the yeast maker's range: SafAle US-05 lists 64–79°F (18–26°C) as ideal, lager strains run cooler and kveik much warmer. Aim for the lower part of the range for clean ales and remember the beer runs warmer than the room.
How do I keep a fermenter cool without a fridge?
An insulated fermentation bag or a tub of water with frozen bottles, swapped once or twice a day, holds an ale several degrees below a warm room. Or brew with kveik.
Can I use a mini fridge as a fermentation chamber?
If the fermenter fits with its airlock, yes. Pair it with a dual-stage controller; a homebrew kegerator can also double as a chamber per Kegco.
Where should I put the controller probe?
Taped against the side of the fermenter under foam or bubble wrap, so it reads the beer, not the air.
What is kveik yeast?
A family of Norwegian farmhouse strains that ferment fast and clean at high temperatures, such as LalBrew Voss (95–104°F optimal per its listing). They are the no-control route for hot garages.